diff --git a/plugins/BigFile/BigfilePiecefield.py b/plugins/BigFile/BigfilePiecefield.py
new file mode 100644
index 00000000..c7690279
--- /dev/null
+++ b/plugins/BigFile/BigfilePiecefield.py
@@ -0,0 +1,158 @@
+import array
+
+
+def packPiecefield(data):
+    res = []
+    if not data:
+        return array.array("H", "")
+
+    if data[0] == "0":
+        res.append(0)
+        find = "1"
+    else:
+        find = "0"
+    last_pos = 0
+    pos = 0
+    while 1:
+        pos = data.find(find, pos)
+        if find == "0":
+            find = "1"
+        else:
+            find = "0"
+        if pos == -1:
+            res.append(len(data) - last_pos)
+            break
+        res.append(pos - last_pos)
+        last_pos = pos
+    return array.array("H", res)
+
+
+def unpackPiecefield(data):
+    if not data:
+        return ""
+
+    res = []
+    char = "1"
+    for times in data:
+        if times > 10000:
+            return ""
+        res.append(char * times)
+        if char == "1":
+            char = "0"
+        else:
+            char = "1"
+    return "".join(res)
+
+
+class BigfilePiecefield(object):
+    __slots__ = ["data"]
+
+    def __init__(self):
+        self.data = ""
+
+    def fromstring(self, s):
+        self.data = s
+
+    def tostring(self):
+        return self.data
+
+    def pack(self):
+        return packPiecefield(self.data).tostring()
+
+    def unpack(self, s):
+        self.data = unpackPiecefield(array.array("H", s))
+
+    def __getitem__(self, key):
+        try:
+            return int(self.data[key])
+        except IndexError:
+            return False
+
+    def __setitem__(self, key, value):
+        data = self.data
+        if len(data) < key:
+            data = data.ljust(key+1, "0")
+        data = data[:key] + str(int(value)) + data[key + 1:]
+        self.data = data
+
+
+class BigfilePiecefieldPacked(object):
+    __slots__ = ["data"]
+
+    def __init__(self):
+        self.data = ""
+
+    def fromstring(self, data):
+        self.data = packPiecefield(data).tostring()
+
+    def tostring(self):
+        return unpackPiecefield(array.array("H", self.data))
+
+    def pack(self):
+        return array.array("H", self.data).tostring()
+
+    def unpack(self, data):
+        self.data = data
+
+    def __getitem__(self, key):
+        try:
+            return int(self.tostring()[key])
+        except IndexError:
+            return False
+
+    def __setitem__(self, key, value):
+        data = self.tostring()
+        if len(data) < key:
+            data = data.ljust(key+1, "0")
+        data = data[:key] + str(int(value)) + data[key + 1:]
+        self.fromstring(data)
+
+
+if __name__ == "__main__":
+    import os
+    import psutil
+    import time
+    testdata = "1" * 100 + "0" * 900 + "1" * 4000 + "0" * 4999 + "1"
+    meminfo = psutil.Process(os.getpid()).memory_info
+
+    for storage in [BigfilePiecefieldPacked, BigfilePiecefield]:
+        print "-- Testing storage: %s --" % storage
+        m = meminfo()[0]
+        s = time.time()
+        piecefields = {}
+        for i in range(10000):
+            piecefield = storage()
+            piecefield.fromstring(testdata[:i] + "0" + testdata[i + 1:])
+            piecefields[i] = piecefield
+
+        print "Create x10000: +%sKB in %.3fs (len: %s)" % ((meminfo()[0] - m) / 1024, time.time() - s, len(piecefields[0].data))
+
+        m = meminfo()[0]
+        s = time.time()
+        for piecefield in piecefields.values():
+            val = piecefield[1000]
+
+        print "Query one x10000: +%sKB in %.3fs" % ((meminfo()[0] - m) / 1024, time.time() - s)
+
+        m = meminfo()[0]
+        s = time.time()
+        for piecefield in piecefields.values():
+            piecefield[1000] = True
+
+        print "Change one x10000: +%sKB in %.3fs" % ((meminfo()[0] - m) / 1024, time.time() - s)
+
+        m = meminfo()[0]
+        s = time.time()
+        for piecefield in piecefields.values():
+            packed = piecefield.pack()
+
+        print "Pack x10000: +%sKB in %.3fs (len: %s)" % ((meminfo()[0] - m) / 1024, time.time() - s, len(packed))
+
+        m = meminfo()[0]
+        s = time.time()
+        for piecefield in piecefields.values():
+            piecefield.unpack(packed)
+
+        print "Unpack x10000: +%sKB in %.3fs (len: %s)" % ((meminfo()[0] - m) / 1024, time.time() - s, len(piecefields[0].data))
+
+        piecefields = {}
diff --git a/plugins/BigFile/BigfilePlugin.py b/plugins/BigFile/BigfilePlugin.py
new file mode 100644
index 00000000..94e1ec7d
--- /dev/null
+++ b/plugins/BigFile/BigfilePlugin.py
@@ -0,0 +1,678 @@
+import time
+import os
+import subprocess
+import shutil
+import collections
+import gevent
+import math
+
+import msgpack
+
+from Plugin import PluginManager
+from Crypt import CryptHash
+from lib import merkletools
+from util import helper
+import util
+from BigfilePiecefield import BigfilePiecefield, BigfilePiecefieldPacked
+
+
+# We can only import plugin host clases after the plugins are loaded
+@PluginManager.afterLoad
+def importPluginnedClasses():
+    global VerifyError, config
+    from Content.ContentManager import VerifyError
+    from Config import config
+
+if "upload_nonces" not in locals():
+    upload_nonces = {}
+
+
+@PluginManager.registerTo("UiRequest")
+class UiRequestPlugin(object):
+    def isCorsAllowed(self, path):
+        if path == "/ZeroNet-Internal/BigfileUpload":
+            return True
+        else:
+            return super(UiRequestPlugin, self).isCorsAllowed(path)
+
+    def actionBigfileUpload(self):
+        nonce = self.get.get("upload_nonce")
+        if nonce not in upload_nonces:
+            return self.error403("Upload nonce error.")
+
+        upload_info = upload_nonces[nonce]
+        del upload_nonces[nonce]
+
+        self.sendHeader(200, "text/html", noscript=True, extra_headers=[
+            ("Access-Control-Allow-Origin", "null"),
+            ("Access-Control-Allow-Credentials", "true")
+        ])
+
+        self.readMultipartHeaders(self.env['wsgi.input'])  # Skip http headers
+
+        site = upload_info["site"]
+        inner_path = upload_info["inner_path"]
+
+        with site.storage.open(inner_path, "wb", create_dirs=True) as out_file:
+            merkle_root, piece_size, piecemap_info = site.content_manager.hashBigfile(
+                self.env['wsgi.input'], upload_info["size"], upload_info["piece_size"], out_file
+            )
+
+        if len(piecemap_info["sha512_pieces"]) == 1:  # Small file, don't split
+            hash = piecemap_info["sha512_pieces"][0].encode("hex")
+            site.content_manager.optionalDownloaded(inner_path, hash, upload_info["size"], own=True)
+
+        else:  # Big file
+            file_name = helper.getFilename(inner_path)
+            msgpack.pack({file_name: piecemap_info}, site.storage.open(upload_info["piecemap"], "wb"))
+
+            # Find piecemap and file relative path to content.json
+            file_info = site.content_manager.getFileInfo(inner_path)
+            content_inner_path_dir = helper.getDirname(file_info["content_inner_path"])
+            piecemap_relative_path = upload_info["piecemap"][len(content_inner_path_dir):]
+            file_relative_path = inner_path[len(content_inner_path_dir):]
+
+            # Add file to content.json
+            if site.storage.isFile(file_info["content_inner_path"]):
+                content = site.storage.loadJson(file_info["content_inner_path"])
+            else:
+                content = {}
+            if "files_optional" not in content:
+                content["files_optional"] = {}
+
+            content["files_optional"][file_relative_path] = {
+                "sha512": merkle_root,
+                "size": upload_info["size"],
+                "piecemap": piecemap_relative_path,
+                "piece_size": piece_size
+            }
+
+            site.content_manager.optionalDownloaded(inner_path, merkle_root, upload_info["size"], own=True)
+            site.storage.writeJson(file_info["content_inner_path"], content)
+
+        return {
+            "merkle_root": merkle_root,
+            "piece_num": len(piecemap_info["sha512_pieces"]),
+            "piece_size": piece_size,
+            "inner_path": inner_path
+        }
+
+    def readMultipartHeaders(self, wsgi_input):
+        for i in range(100):
+            line = wsgi_input.readline()
+            if line == "\r\n":
+                break
+        return i
+
+    def actionFile(self, file_path, *args, **kwargs):
+        if kwargs.get("file_size", 0) > 1024 * 1024 and kwargs.get("path_parts"):  # Only check files larger than 1MB
+            path_parts = kwargs["path_parts"]
+            site = self.server.site_manager.get(path_parts["address"])
+            kwargs["file_obj"] = site.storage.openBigfile(path_parts["inner_path"], prebuffer=2 * 1024 * 1024)
+
+        return super(UiRequestPlugin, self).actionFile(file_path, *args, **kwargs)
+
+
+@PluginManager.registerTo("UiWebsocket")
+class UiWebsocketPlugin(object):
+    def actionBigfileUploadInit(self, to, inner_path, size):
+        valid_signers = self.site.content_manager.getValidSigners(inner_path)
+        auth_address = self.user.getAuthAddress(self.site.address)
+        if not self.site.settings["own"] and auth_address not in valid_signers:
+            self.log.error("FileWrite forbidden %s not in valid_signers %s" % (auth_address, valid_signers))
+            return self.response(to, {"error": "Forbidden, you can only modify your own files"})
+
+        nonce = CryptHash.random()
+        piece_size = 1024 * 1024
+        inner_path = self.site.content_manager.sanitizePath(inner_path)
+        file_info = self.site.content_manager.getFileInfo(inner_path)
+
+        content_inner_path_dir = helper.getDirname(file_info["content_inner_path"])
+        file_relative_path = inner_path[len(content_inner_path_dir):]
+
+        upload_nonces[nonce] = {
+            "added": time.time(),
+            "site": self.site,
+            "inner_path": inner_path,
+            "websocket_client": self,
+            "size": size,
+            "piece_size": piece_size,
+            "piecemap": inner_path + ".piecemap.msgpack"
+        }
+        self.response(to, {
+            "url": "/ZeroNet-Internal/BigfileUpload?upload_nonce=" + nonce,
+            "pice_size": piece_size,
+            "inner_path": inner_path,
+            "file_relative_path": file_relative_path
+        })
+
+
+@PluginManager.registerTo("ContentManager")
+class ContentManagerPlugin(object):
+    def getFileInfo(self, inner_path):
+        if "|" not in inner_path:
+            return super(ContentManagerPlugin, self).getFileInfo(inner_path)
+
+        inner_path, file_range = inner_path.split("|")
+        pos_from, pos_to = map(int, file_range.split("-"))
+        file_info = super(ContentManagerPlugin, self).getFileInfo(inner_path)
+        return file_info
+
+    def readFile(self, file_in, size, buff_size=1024 * 64):
+        part_num = 0
+        recv_left = size
+
+        while 1:
+            part_num += 1
+            read_size = min(buff_size, recv_left)
+            part = file_in.read(read_size)
+
+            if not part:
+                break
+            yield part
+
+            if part_num % 100 == 0:  # Avoid blocking ZeroNet execution during upload
+                time.sleep(0.001)
+
+            recv_left -= read_size
+            if recv_left <= 0:
+                break
+
+    def hashBigfile(self, file_in, size, piece_size=1024 * 1024, file_out=None):
+        self.site.settings["has_bigfile"] = True
+
+        recv = 0
+        try:
+            piece_hash = CryptHash.sha512t()
+            piece_hashes = []
+            piece_recv = 0
+
+            mt = merkletools.MerkleTools()
+            mt.hash_function = CryptHash.sha512t
+
+            part = ""
+            for part in self.readFile(file_in, size):
+                if file_out:
+                    file_out.write(part)
+
+                recv += len(part)
+                piece_recv += len(part)
+                piece_hash.update(part)
+                if piece_recv >= piece_size:
+                    piece_digest = piece_hash.digest()
+                    piece_hashes.append(piece_digest)
+                    mt.leaves.append(piece_digest)
+                    piece_hash = CryptHash.sha512t()
+                    piece_recv = 0
+
+                    if len(piece_hashes) % 100 == 0 or recv == size:
+                        self.log.info("- [HASHING:%.0f%%] Pieces: %s, %.1fMB/%.1fMB" % (
+                            float(recv) / size * 100, len(piece_hashes), recv / 1024 / 1024, size / 1024 / 1024
+                        ))
+                        part = ""
+            if len(part) > 0:
+                piece_digest = piece_hash.digest()
+                piece_hashes.append(piece_digest)
+                mt.leaves.append(piece_digest)
+        except Exception as err:
+            raise err
+        finally:
+            if file_out:
+                file_out.close()
+
+        mt.make_tree()
+        return mt.get_merkle_root(), piece_size, {
+            "sha512_pieces": piece_hashes
+        }
+
+    def hashFile(self, dir_inner_path, file_relative_path, optional=False):
+        inner_path = dir_inner_path + file_relative_path
+
+        file_size = self.site.storage.getSize(inner_path)
+        # Only care about optional files >1MB
+        if not optional or file_size < 1 * 1024 * 1024:
+            return super(ContentManagerPlugin, self).hashFile(dir_inner_path, file_relative_path, optional)
+
+        back = {}
+        content = self.contents.get(dir_inner_path + "content.json")
+
+        hash = None
+        piecemap_relative_path = None
+        piece_size = None
+
+        # Don't re-hash if it's already in content.json
+        if content and file_relative_path in content.get("files_optional"):
+            file_node = content["files_optional"][file_relative_path]
+            if file_node["size"] == file_size:
+                self.log.info("- [SAME SIZE] %s" % file_relative_path)
+                hash = file_node.get("sha512")
+                piecemap_relative_path = file_node.get("piecemap")
+                piece_size = file_node.get("piece_size")
+
+        if not hash or not piecemap_relative_path:  # Not in content.json yet
+            if file_size < 5 * 1024 * 1024:  # Don't create piecemap automatically for files smaller than 5MB
+                return super(ContentManagerPlugin, self).hashFile(dir_inner_path, file_relative_path, optional)
+
+            self.log.info("- [HASHING] %s" % file_relative_path)
+            merkle_root, piece_size, piecemap_info = self.hashBigfile(self.site.storage.open(inner_path, "rb"), file_size)
+            if not hash:
+                hash = merkle_root
+
+            if not piecemap_relative_path:
+                file_name = helper.getFilename(file_relative_path)
+                piecemap_relative_path = file_relative_path + ".piecemap.msgpack"
+                piecemap_inner_path = inner_path + ".piecemap.msgpack"
+
+                msgpack.pack({file_name: piecemap_info}, self.site.storage.open(piecemap_inner_path, "wb"))
+                back.update(super(ContentManagerPlugin, self).hashFile(dir_inner_path, piecemap_relative_path, True))
+
+        piece_num = int(math.ceil(float(file_size) / piece_size))
+
+        # Add the merkle root to hashfield
+        self.optionalDownloaded(inner_path, hash, file_size, own=True)
+        self.site.storage.piecefields[hash].fromstring("1" * piece_num)
+
+        back[file_relative_path] = {"sha512": hash, "size": file_size, "piecemap": piecemap_relative_path, "piece_size": piece_size}
+        return back
+
+    def getPiecemap(self, inner_path):
+        file_info = self.site.content_manager.getFileInfo(inner_path)
+        piecemap_inner_path = helper.getDirname(file_info["content_inner_path"]) + file_info["piecemap"]
+        self.site.needFile(piecemap_inner_path, priority=20)
+        piecemap = msgpack.unpack(self.site.storage.open(piecemap_inner_path))[helper.getFilename(inner_path)]
+        piecemap["piece_size"] = file_info["piece_size"]
+        return piecemap
+
+    def verifyPiece(self, inner_path, pos, piece):
+        piecemap = self.getPiecemap(inner_path)
+        piece_i = pos / piecemap["piece_size"]
+        if CryptHash.sha512sum(piece, format="digest") != piecemap["sha512_pieces"][piece_i]:
+            raise VerifyError("Invalid hash")
+        return True
+
+    def verifyFile(self, inner_path, file, ignore_same=True):
+        if "|" not in inner_path:
+            return super(ContentManagerPlugin, self).verifyFile(inner_path, file, ignore_same)
+
+        inner_path, file_range = inner_path.split("|")
+        pos_from, pos_to = map(int, file_range.split("-"))
+
+        return self.verifyPiece(inner_path, pos_from, file)
+
+    def optionalDownloaded(self, inner_path, hash, size=None, own=False):
+        if "|" in inner_path:
+            inner_path, file_range = inner_path.split("|")
+            pos_from, pos_to = map(int, file_range.split("-"))
+            file_info = self.getFileInfo(inner_path)
+
+            # Mark piece downloaded
+            piece_i = pos_from / file_info["piece_size"]
+            self.site.storage.piecefields[file_info["sha512"]][piece_i] = True
+
+            # Only add to site size on first request
+            if hash in self.hashfield:
+                size = 0
+
+        return super(ContentManagerPlugin, self).optionalDownloaded(inner_path, hash, size, own)
+
+    def optionalRemove(self, inner_path, hash, size=None):
+        if size and size > 1024 * 1024:
+            file_info = self.getFileInfo(inner_path)
+            sha512 = file_info["sha512"]
+            if sha512 in self.site.storage.piecefields:
+                del self.site.storage.piecefields[sha512]
+        return super(ContentManagerPlugin, self).optionalRemove(inner_path, hash, size)
+
+
+@PluginManager.registerTo("SiteStorage")
+class SiteStoragePlugin(object):
+    def __init__(self, *args, **kwargs):
+        super(SiteStoragePlugin, self).__init__(*args, **kwargs)
+        self.piecefields = collections.defaultdict(BigfilePiecefield)
+        if "piecefields" in self.site.settings.get("cache", {}):
+            for sha512, piecefield_packed in self.site.settings["cache"].get("piecefields").iteritems():
+                self.piecefields[sha512].unpack(piecefield_packed.decode("base64"))
+            self.site.settings["cache"]["piecefields"] = {}
+
+    def createSparseFile(self, inner_path, size, sha512=None):
+        file_path = self.getPath(inner_path)
+        f = open(file_path, 'wb')
+        f.truncate(size)
+        f.close()
+        if os.name == "nt":
+            subprocess.call(["fsutil", "sparse", "setflag", file_path])
+
+        if sha512 and sha512 in self.piecefields:
+            self.log.debug("%s: File not exists, but has piecefield. Deleting piecefield." % inner_path)
+            del self.piecefields[sha512]
+
+    def write(self, inner_path, content):
+        if "|" not in inner_path:
+            return super(SiteStoragePlugin, self).write(inner_path, content)
+
+        # Write to specific position by passing |{pos} after the filename
+        inner_path, file_range = inner_path.split("|")
+        pos_from, pos_to = map(int, file_range.split("-"))
+        file_path = self.getPath(inner_path)
+
+        # Create dir if not exist
+        file_dir = os.path.dirname(file_path)
+        if not os.path.isdir(file_dir):
+            os.makedirs(file_dir)
+
+        if not os.path.isfile(file_path):
+            file_info = self.site.content_manager.getFileInfo(inner_path)
+            self.createSparseFile(inner_path, file_info["size"])
+
+        # Write file
+        with open(file_path, "rb+") as file:
+            file.seek(pos_from)
+            if hasattr(content, 'read'):  # File-like object
+                shutil.copyfileobj(content, file)  # Write buff to disk
+            else:  # Simple string
+                file.write(content)
+        del content
+        self.onUpdated(inner_path)
+
+    def openBigfile(self, inner_path, prebuffer=0):
+        file_info = self.site.content_manager.getFileInfo(inner_path)
+        if "piecemap" not in file_info:  # It's not a big file
+            return False
+
+        self.site.needFile(inner_path, blocking=False)  # Download piecemap
+        file_path = self.getPath(inner_path)
+        sha512 = file_info["sha512"]
+        piece_num = int(math.ceil(float(file_info["size"]) / file_info["piece_size"]))
+        if os.path.isfile(file_path):
+            if sha512 not in self.piecefields:
+                if open(file_path).read(128) == "\0" * 128:
+                    piece_data = "0"
+                else:
+                    piece_data = "1"
+                self.log.debug("%s: File exists, but not in piecefield. Filling piecefiled with %s * %s." % (inner_path, piece_num, piece_data))
+                self.piecefields[sha512].fromstring(piece_data * piece_num)
+        else:
+            self.log.debug("Creating bigfile: %s" % inner_path)
+            self.createSparseFile(inner_path, file_info["size"], sha512)
+            self.piecefields[sha512].fromstring(piece_data * "0")
+        return BigFile(self.site, inner_path, prebuffer=prebuffer)
+
+
+class BigFile(object):
+    def __init__(self, site, inner_path, prebuffer=0):
+        self.site = site
+        self.inner_path = inner_path
+        file_path = site.storage.getPath(inner_path)
+        file_info = self.site.content_manager.getFileInfo(inner_path)
+        self.piece_size = file_info["piece_size"]
+        self.sha512 = file_info["sha512"]
+        self.size = file_info["size"]
+        self.prebuffer = prebuffer
+        self.read_bytes = 0
+
+        self.piecefield = self.site.storage.piecefields[self.sha512]
+        self.f = open(file_path, "rb+")
+
+    def read(self, buff=64 * 1024):
+        pos = self.f.tell()
+        read_until = pos + buff
+        requests = []
+        # Request all required blocks
+        while 1:
+            piece_i = pos / self.piece_size
+            if piece_i * self.piece_size >= read_until:
+                break
+            pos_from = piece_i * self.piece_size
+            pos_to = pos_from + self.piece_size
+            if not self.piecefield[piece_i]:
+                requests.append(self.site.needFile("%s|%s-%s" % (self.inner_path, pos_from, pos_to), blocking=False, update=True, priority=10))
+            pos += self.piece_size
+
+        if not all(requests):
+            return None
+
+        # Request prebuffer
+        if self.prebuffer:
+            prebuffer_until = min(self.size, read_until + self.prebuffer)
+            priority = 3
+            while 1:
+                piece_i = pos / self.piece_size
+                if piece_i * self.piece_size >= prebuffer_until:
+                    break
+                pos_from = piece_i * self.piece_size
+                pos_to = pos_from + self.piece_size
+                if not self.piecefield[piece_i]:
+                    self.site.needFile("%s|%s-%s" % (self.inner_path, pos_from, pos_to), blocking=False, update=True, priority=max(0, priority))
+                priority -= 1
+                pos += self.piece_size
+
+        gevent.joinall(requests)
+        self.read_bytes += buff
+
+        # Increase buffer for long reads
+        if self.read_bytes > 7 * 1024 * 1024 and self.prebuffer < 5 * 1024 * 1024:
+            self.site.log.debug("%s: Increasing bigfile buffer size to 5MB..." % self.inner_path)
+            self.prebuffer = 5 * 1024 * 1024
+
+        return self.f.read(buff)
+
+    def seek(self, pos):
+        return self.f.seek(pos)
+
+    def tell(self):
+        self.f.tell()
+
+    def close(self):
+        self.f.close()
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        self.close()
+
+
+@PluginManager.registerTo("WorkerManager")
+class WorkerManagerPlugin(object):
+    def addTask(self, inner_path, *args, **kwargs):
+        file_info = kwargs.get("file_info")
+        if file_info and "piecemap" in file_info:  # Bigfile
+            self.site.settings["has_bigfile"] = True
+
+            piecemap_inner_path = helper.getDirname(file_info["content_inner_path"]) + file_info["piecemap"]
+            piecemap_task = None
+            if not self.site.storage.isFile(piecemap_inner_path):
+                # Start download piecemap
+                piecemap_task = super(WorkerManagerPlugin, self).addTask(piecemap_inner_path, priority=30)
+                if "|" not in inner_path and self.site.isDownloadable(inner_path) and file_info["size"] / 1024 / 1024 <= config.autodownload_bigfile_size_limit:
+                    gevent.spawn_later(0.1, self.site.needFile, inner_path + "|all")  # Download all pieces
+
+            if "|" in inner_path:
+                # Start download piece
+                task = super(WorkerManagerPlugin, self).addTask(inner_path, *args, **kwargs)
+
+                inner_path, file_range = inner_path.split("|")
+                pos_from, pos_to = map(int, file_range.split("-"))
+                task["piece_i"] = pos_from / file_info["piece_size"]
+                task["sha512"] = file_info["sha512"]
+            else:
+                if inner_path in self.site.bad_files:
+                    del self.site.bad_files[inner_path]
+                if piecemap_task:
+                    task = piecemap_task
+                else:
+                    fake_evt = gevent.event.AsyncResult()  # Don't download anything if no range specified
+                    fake_evt.set(True)
+                    task = {"evt": fake_evt}
+
+            if not self.site.storage.isFile(inner_path):
+                self.site.storage.createSparseFile(inner_path, file_info["size"], file_info["sha512"])
+                piece_num = int(math.ceil(float(file_info["size"]) / file_info["piece_size"]))
+                self.site.storage.piecefields[file_info["sha512"]].fromstring("0" * piece_num)
+        else:
+            task = super(WorkerManagerPlugin, self).addTask(inner_path, *args, **kwargs)
+        return task
+
+    def taskAddPeer(self, task, peer):
+        if "piece_i" in task:
+            if not peer.piecefields[task["sha512"]][task["piece_i"]]:
+                if task["sha512"] not in peer.piecefields:
+                    gevent.spawn(peer.updatePiecefields, force=True)
+                elif not task["peers"]:
+                    gevent.spawn(peer.updatePiecefields)
+
+                return False  # Deny to add peers to task if file not in piecefield
+        return super(WorkerManagerPlugin, self).taskAddPeer(task, peer)
+
+
+@PluginManager.registerTo("FileRequest")
+class FileRequestPlugin(object):
+    def isReadable(self, site, inner_path, file, pos):
+        # Peek into file
+        if file.read(10) == "\0" * 10:
+            # Looks empty, but makes sures we don't have that piece
+            file_info = site.content_manager.getFileInfo(inner_path)
+            piece_i = pos / file_info["piece_size"]
+            if not site.storage.piecefields[file_info["sha512"]][piece_i]:
+                return False
+        # Seek back to position we want to read
+        file.seek(pos)
+        return super(FileRequestPlugin, self).isReadable(site, inner_path, file, pos)
+
+    def actionGetPiecefields(self, params):
+        site = self.sites.get(params["site"])
+        if not site or not site.settings["serving"]:  # Site unknown or not serving
+            self.response({"error": "Unknown site"})
+            return False
+
+        # Add peer to site if not added before
+        peer = site.addPeer(self.connection.ip, self.connection.port, return_peer=True)
+        if not peer.connection:  # Just added
+            peer.connect(self.connection)  # Assign current connection to peer
+
+        piecefields_packed = {sha512: piecefield.pack() for sha512, piecefield in site.storage.piecefields.iteritems()}
+        self.response({"piecefields_packed": piecefields_packed})
+
+    def actionSetPiecefields(self, params):
+        site = self.sites.get(params["site"])
+        if not site or not site.settings["serving"]:  # Site unknown or not serving
+            self.response({"error": "Unknown site"})
+            self.connection.badAction(5)
+            return False
+
+        # Add or get peer
+        peer = site.addPeer(self.connection.ip, self.connection.port, return_peer=True, connection=self.connection)
+        if not peer.connection:
+            peer.connect(self.connection)
+
+        peer.piecefields = collections.defaultdict(BigfilePiecefieldPacked)
+        for sha512, piecefield_packed in params["piecefields_packed"].iteritems():
+            peer.piecefields[sha512].unpack(piecefield_packed)
+        site.settings["has_bigfile"] = True
+
+        self.response({"ok": "Updated"})
+
+
+@PluginManager.registerTo("Peer")
+class PeerPlugin(object):
+    def __getattr__(self, key):
+        if key == "piecefields":
+            self.piecefields = collections.defaultdict(BigfilePiecefieldPacked)
+            return self.piecefields
+        elif key == "time_piecefields_updated":
+            self.time_piecefields_updated = None
+            return self.time_piecefields_updated
+        else:
+            return super(PeerPlugin, self).__getattr__(key)
+
+    @util.Noparallel(ignore_args=True)
+    def updatePiecefields(self, force=False):
+        if self.connection and self.connection.handshake.get("rev", 0) < 2190:
+            return False  # Not supported
+
+        # Don't update piecefield again in 1 min
+        if self.time_piecefields_updated and time.time() - self.time_piecefields_updated < 60 and not force:
+            return False
+
+        self.time_piecefields_updated = time.time()
+        res = self.request("getPiecefields", {"site": self.site.address})
+        if not res or "error" in res:
+            return False
+
+        self.piecefields = collections.defaultdict(BigfilePiecefieldPacked)
+        for sha512, piecefield_packed in res["piecefields_packed"].iteritems():
+            self.piecefields[sha512].unpack(piecefield_packed)
+
+        return self.piecefields
+
+    def sendMyHashfield(self, *args, **kwargs):
+        return super(PeerPlugin, self).sendMyHashfield(*args, **kwargs)
+
+    def updateHashfield(self, *args, **kwargs):
+        if self.site.settings.get("has_bigfile"):
+            thread = gevent.spawn(self.updatePiecefields, *args, **kwargs)
+            back = super(PeerPlugin, self).updateHashfield(*args, **kwargs)
+            thread.join()
+            return back
+        else:
+            return super(PeerPlugin, self).updateHashfield(*args, **kwargs)
+
+    def getFile(self, site, inner_path, *args, **kwargs):
+        if "|" in inner_path:
+            inner_path, file_range = inner_path.split("|")
+            pos_from, pos_to = map(int, file_range.split("-"))
+            kwargs["pos_from"] = pos_from
+            kwargs["pos_to"] = pos_to
+        return super(PeerPlugin, self).getFile(site, inner_path, *args, **kwargs)
+
+
+@PluginManager.registerTo("Site")
+class SitePlugin(object):
+    def isFileDownloadAllowed(self, inner_path, file_info):
+        if "piecemap" in file_info:
+            file_info = file_info.copy()
+            file_info["size"] = file_info["piece_size"]
+        return super(SitePlugin, self).isFileDownloadAllowed(inner_path, file_info)
+
+    def getSettingsCache(self):
+        back = super(SitePlugin, self).getSettingsCache()
+        if self.storage.piecefields:
+            back["piecefields"] = {sha512: piecefield.pack().encode("base64") for sha512, piecefield in self.storage.piecefields.iteritems()}
+        return back
+
+    def needFile(self, inner_path, *args, **kwargs):
+        if inner_path.endswith("|all"):
+            @util.Pooled(20)
+            def pooledNeedBigfile(*args, **kwargs):
+                return self.needFile(*args, **kwargs)
+
+            inner_path = inner_path.replace("|all", "")
+            file_info = self.needFileInfo(inner_path)
+            file_size = file_info["size"]
+            piece_size = file_info["piece_size"]
+
+            piece_num = int(math.ceil(float(file_size) / piece_size))
+
+            file_threads = []
+
+            piecefield = self.storage.piecefields.get(file_info["sha512"])
+
+            for piece_i in range(piece_num):
+                piece_from = piece_i * piece_size
+                piece_to = min(file_size, piece_from + piece_size)
+                if not piecefield or not piecefield[piece_i]:
+                    res = pooledNeedBigfile("%s|%s-%s" % (inner_path, piece_from, piece_to), blocking=False)
+                    if res is not True and res is not False:
+                        file_threads.append(res)
+            gevent.joinall(file_threads)
+        else:
+            return super(SitePlugin, self).needFile(inner_path, *args, **kwargs)
+
+
+@PluginManager.registerTo("ConfigPlugin")
+class ConfigPlugin(object):
+    def createArguments(self):
+        group = self.parser.add_argument_group("Bigfile plugin")
+        group.add_argument('--autodownload_bigfile_size_limit', help='Also download bigfiles until this limit if help distribute option is checked', default=1, metavar="MB", type=int)
+
+        return super(ConfigPlugin, self).createArguments()
diff --git a/plugins/BigFile/Test/TestBigfile.py b/plugins/BigFile/Test/TestBigfile.py
new file mode 100644
index 00000000..a934a67c
--- /dev/null
+++ b/plugins/BigFile/Test/TestBigfile.py
@@ -0,0 +1,467 @@
+import time
+import os
+from cStringIO import StringIO
+
+import pytest
+import msgpack
+import mock
+from lib import merkletools
+
+from Connection import ConnectionServer
+from Content.ContentManager import VerifyError
+from File import FileServer
+from File import FileRequest
+from Worker import WorkerManager
+from Peer import Peer
+from Bigfile import BigfilePiecefield, BigfilePiecefieldPacked
+from Test import Spy
+
+
+@pytest.mark.usefixtures("resetSettings")
+@pytest.mark.usefixtures("resetTempSettings")
+class TestBigfile:
+    privatekey = "5KUh3PvNm5HUWoCfSUfcYvfQ2g3PrRNJWr6Q9eqdBGu23mtMntv"
+
+    def createBigfile(self, site, inner_path="data/optional.any.iso", pieces=10):
+        f = site.storage.open(inner_path, "w")
+        for i in range(pieces * 100):
+            f.write(("Test%s" % i).ljust(10, "-") * 1000)
+        f.close()
+        assert site.content_manager.sign("content.json", self.privatekey)
+        return inner_path
+
+    def testPiecemapCreate(self, site):
+        inner_path = self.createBigfile(site)
+        content = site.storage.loadJson("content.json")
+        assert "data/optional.any.iso" in content["files_optional"]
+        file_node = content["files_optional"][inner_path]
+        assert file_node["size"] == 10 * 1000 * 1000
+        assert file_node["sha512"] == "47a72cde3be80b4a829e7674f72b7c6878cf6a70b0c58c6aa6c17d7e9948daf6"
+        assert file_node["piecemap"] == inner_path + ".piecemap.msgpack"
+
+        piecemap = msgpack.unpack(site.storage.open(file_node["piecemap"], "rb"))["optional.any.iso"]
+        assert len(piecemap["sha512_pieces"]) == 10
+        assert piecemap["sha512_pieces"][0] != piecemap["sha512_pieces"][1]
+        assert piecemap["sha512_pieces"][0].encode("hex") == "a73abad9992b3d0b672d0c2a292046695d31bebdcb1e150c8410bbe7c972eff3"
+
+    def testVerifyPiece(self, site):
+        inner_path = self.createBigfile(site)
+
+        # Verify all 10 piece
+        f = site.storage.open(inner_path, "rb")
+        for i in range(10):
+            piece = StringIO(f.read(1024 * 1024))
+            piece.seek(0)
+            site.content_manager.verifyPiece(inner_path, i * 1024 * 1024, piece)
+        f.close()
+
+        # Try to verify piece 0 with piece 1 hash
+        with pytest.raises(VerifyError) as err:
+            i = 1
+            f = site.storage.open(inner_path, "rb")
+            piece = StringIO(f.read(1024 * 1024))
+            f.close()
+            site.content_manager.verifyPiece(inner_path, i * 1024 * 1024, piece)
+        assert "Invalid hash" in str(err)
+
+    def testSparseFile(self, site):
+        inner_path = "sparsefile"
+
+        # Create a 100MB sparse file
+        site.storage.createSparseFile(inner_path, 100 * 1024 * 1024)
+
+        # Write to file beginning
+        s = time.time()
+        f = site.storage.write("%s|%s-%s" % (inner_path, 0, 1024 * 1024), "hellostart" * 1024)
+        time_write_start = time.time() - s
+
+        # Write to file end
+        s = time.time()
+        f = site.storage.write("%s|%s-%s" % (inner_path, 99 * 1024 * 1024, 99 * 1024 * 1024 + 1024 * 1024), "helloend" * 1024)
+        time_write_end = time.time() - s
+
+        # Verify writes
+        f = site.storage.open(inner_path)
+        assert f.read(10) == "hellostart"
+        f.seek(99 * 1024 * 1024)
+        assert f.read(8) == "helloend"
+        f.close()
+
+        site.storage.delete(inner_path)
+
+        # Writing to end shold not take much longer, than writing to start
+        assert time_write_end <= max(0.1, time_write_start * 1.1)
+
+    def testRangedFileRequest(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        file_server.sites[site.address] = site
+        client = FileServer("127.0.0.1", 1545)
+        client.sites[site_temp.address] = site_temp
+        site_temp.connection_server = client
+        connection = client.getConnection("127.0.0.1", 1544)
+
+        # Add file_server as peer to client
+        peer_file_server = site_temp.addPeer("127.0.0.1", 1544)
+
+        buff = peer_file_server.getFile(site_temp.address, "%s|%s-%s" % (inner_path, 5 * 1024 * 1024, 6 * 1024 * 1024))
+
+        assert len(buff.getvalue()) == 1 * 1024 * 1024  # Correct block size
+        assert buff.getvalue().startswith("Test524")  # Correct data
+        buff.seek(0)
+        assert site.content_manager.verifyPiece(inner_path, 5 * 1024 * 1024, buff)  # Correct hash
+
+        connection.close()
+        client.stop()
+
+    def testRangedFileDownload(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        # Init source server
+        site.connection_server = file_server
+        file_server.sites[site.address] = site
+
+        # Make sure the file and the piecemap in the optional hashfield
+        file_info = site.content_manager.getFileInfo(inner_path)
+        assert site.content_manager.hashfield.hasHash(file_info["sha512"])
+
+        piecemap_hash = site.content_manager.getFileInfo(file_info["piecemap"])["sha512"]
+        assert site.content_manager.hashfield.hasHash(piecemap_hash)
+
+        # Init client server
+        client = ConnectionServer("127.0.0.1", 1545)
+        site_temp.connection_server = client
+        peer_client = site_temp.addPeer("127.0.0.1", 1544)
+
+        # Download site
+        site_temp.download(blind_includes=True).join(timeout=5)
+
+        bad_files = site_temp.storage.verifyFiles(quick_check=True)
+        assert not bad_files
+
+        # client_piecefield = peer_client.piecefields[file_info["sha512"]].tostring()
+        # assert client_piecefield == "1" * 10
+
+        # Download 5. and 10. block
+
+        site_temp.needFile("%s|%s-%s" % (inner_path, 5 * 1024 * 1024, 6 * 1024 * 1024))
+        site_temp.needFile("%s|%s-%s" % (inner_path, 9 * 1024 * 1024, 10 * 1024 * 1024))
+
+        # Verify 0. block not downloaded
+        f = site_temp.storage.open(inner_path)
+        assert f.read(10) == "\0" * 10
+        # Verify 5. and 10. block downloaded
+        f.seek(5 * 1024 * 1024)
+        assert f.read(7) == "Test524"
+        f.seek(9 * 1024 * 1024)
+        assert f.read(7) == "943---T"
+
+        # Verify hashfield
+        assert set(site_temp.content_manager.hashfield) == set([18343, 30970])  # 18343: data/optional.any.iso, 30970: data/optional.any.iso.hashmap.msgpack
+
+    def testOpenBigfile(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        # Init source server
+        site.connection_server = file_server
+        file_server.sites[site.address] = site
+
+        # Init client server
+        client = ConnectionServer("127.0.0.1", 1545)
+        site_temp.connection_server = client
+        site_temp.addPeer("127.0.0.1", 1544)
+
+        # Download site
+        site_temp.download(blind_includes=True).join(timeout=5)
+
+        # Open virtual file
+        assert not site_temp.storage.isFile(inner_path)
+
+        with site_temp.storage.openBigfile(inner_path) as f:
+            with Spy.Spy(FileRequest, "route") as requests:
+                f.seek(5 * 1024 * 1024)
+                assert f.read(7) == "Test524"
+
+                f.seek(9 * 1024 * 1024)
+                assert f.read(7) == "943---T"
+
+            assert len(requests) == 4  # 1x peicemap + 1x getpiecefield + 2x for pieces
+
+            assert set(site_temp.content_manager.hashfield) == set([18343, 30970])
+
+            assert site_temp.storage.piecefields[f.sha512].tostring() == "0000010001"
+            assert f.sha512 in site_temp.getSettingsCache()["piecefields"]
+
+            # Test requesting already downloaded
+            with Spy.Spy(FileRequest, "route") as requests:
+                f.seek(5 * 1024 * 1024)
+                assert f.read(7) == "Test524"
+
+            assert len(requests) == 0
+
+            # Test requesting multi-block overflow reads
+            with Spy.Spy(FileRequest, "route") as requests:
+                f.seek(5 * 1024 * 1024)  # We already have this block
+                data = f.read(1024 * 1024 * 3)  # Our read overflow to 6. and 7. block
+                assert data.startswith("Test524")
+                assert data.endswith("Test838-")
+                assert "\0" not in data  # No null bytes allowed
+
+            assert len(requests) == 2  # Two block download
+
+
+    @pytest.mark.parametrize("piecefield_obj", [BigfilePiecefield, BigfilePiecefieldPacked])
+    def testPiecefield(self, piecefield_obj, site):
+        testdatas = [
+            "1" * 100 + "0" * 900 + "1" * 4000 + "0" * 4999 + "1",
+            "010101" * 10 + "01" * 90 + "10" * 400 + "0" * 4999,
+            "1" * 10000,
+            "0" * 10000
+        ]
+        for testdata in testdatas:
+            piecefield = piecefield_obj()
+
+            piecefield.fromstring(testdata)
+            assert piecefield.tostring() == testdata
+            assert piecefield[0] == int(testdata[0])
+            assert piecefield[100] == int(testdata[100])
+            assert piecefield[1000] == int(testdata[1000])
+            assert piecefield[len(testdata)-1] == int(testdata[len(testdata)-1])
+
+            packed = piecefield.pack()
+            piecefield_new = piecefield_obj()
+            piecefield_new.unpack(packed)
+            assert piecefield.tostring() == piecefield_new.tostring()
+            assert piecefield_new.tostring() == testdata
+
+
+    def testFileGet(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        # Init source server
+        site.connection_server = file_server
+        file_server.sites[site.address] = site
+
+        # Init client server
+        site_temp.connection_server = FileServer("127.0.0.1", 1545)
+        site_temp.connection_server.sites[site_temp.address] = site_temp
+        site_temp.addPeer("127.0.0.1", 1544)
+
+        # Download site
+        site_temp.download(blind_includes=True).join(timeout=5)
+
+        # Download second block
+        with site_temp.storage.openBigfile(inner_path) as f:
+            f.seek(1024 * 1024)
+            assert f.read(1024)[0] != "\0"
+
+        # Make sure first block not download
+        with site_temp.storage.open(inner_path) as f:
+            assert f.read(1024)[0] == "\0"
+
+        peer2 = site.addPeer("127.0.0.1", 1545, return_peer=True)
+
+        # Should drop error on first block request
+        assert not peer2.getFile(site.address, "%s|0-%s" % (inner_path, 1024 * 1024 * 1))
+
+        # Should not drop error for second block request
+        assert peer2.getFile(site.address, "%s|%s-%s" % (inner_path, 1024 * 1024 * 1, 1024 * 1024 * 2))
+
+
+    def benchmarkPeerMemory(self, site, file_server):
+        # Init source server
+        site.connection_server = file_server
+        file_server.sites[site.address] = site
+
+        import psutil, os
+        meminfo = psutil.Process(os.getpid()).memory_info
+
+        mem_s = meminfo()[0]
+        s = time.time()
+        for i in range(25000):
+            site.addPeer("127.0.0.1", i)
+        print "%.3fs MEM: + %sKB" % (time.time() - s, (meminfo()[0] - mem_s) / 1024)  # 0.082s MEM: + 6800KB
+        print site.peers.values()[0].piecefields
+
+
+    def testUpdatePiecefield(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        server1 = file_server
+        server1.sites[site.address] = site
+        server2 = FileServer("127.0.0.1", 1545)
+        server2.sites[site_temp.address] = site_temp
+        site_temp.connection_server = server2
+
+        # Add file_server as peer to client
+        server2_peer1 = site_temp.addPeer("127.0.0.1", 1544)
+
+        # Testing piecefield sync
+        assert len(server2_peer1.piecefields) == 0
+        assert server2_peer1.updatePiecefields()  # Query piecefields from peer
+        assert len(server2_peer1.piecefields) > 0
+
+    def testWorkerManagerPiecefieldDeny(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        server1 = file_server
+        server1.sites[site.address] = site
+        server2 = FileServer("127.0.0.1", 1545)
+        server2.sites[site_temp.address] = site_temp
+        site_temp.connection_server = server2
+
+        # Add file_server as peer to client
+        server2_peer1 = site_temp.addPeer("127.0.0.1", 1544)  # Working
+
+        site_temp.downloadContent("content.json", download_files=False)
+        site_temp.needFile("data/optional.any.iso.piecemap.msgpack")
+
+        # Add fake peers with optional files downloaded
+        for i in range(5):
+            fake_peer = site_temp.addPeer("127.0.1.%s" % i, 1544)
+            fake_peer.hashfield = site.content_manager.hashfield
+            fake_peer.has_hashfield = True
+
+        with Spy.Spy(WorkerManager, "addWorker") as requests:
+            site_temp.needFile("%s|%s-%s" % (inner_path, 5 * 1024 * 1024, 6 * 1024 * 1024))
+            site_temp.needFile("%s|%s-%s" % (inner_path, 6 * 1024 * 1024, 7 * 1024 * 1024))
+
+        # It should only request parts from peer1 as the other peers does not have the requested parts in piecefields
+        assert len([request[1] for request in requests if request[1] != server2_peer1]) == 0
+
+
+    def testWorkerManagerPiecefieldDownload(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        server1 = file_server
+        server1.sites[site.address] = site
+        server2 = FileServer("127.0.0.1", 1545)
+        server2.sites[site_temp.address] = site_temp
+        site_temp.connection_server = server2
+        sha512 = site.content_manager.getFileInfo(inner_path)["sha512"]
+
+        # Create 10 fake peer for each piece
+        for i in range(10):
+            peer = Peer("127.0.0.1", 1544, site_temp, server2)
+            peer.piecefields[sha512][i] = "1"
+            peer.updateHashfield = mock.MagicMock(return_value=False)
+            peer.updatePiecefields = mock.MagicMock(return_value=False)
+            peer.findHashIds = mock.MagicMock(return_value={"nope": []})
+            peer.hashfield = site.content_manager.hashfield
+            peer.has_hashfield = True
+            peer.key = "Peer:%s" % i
+            site_temp.peers["Peer:%s" % i] = peer
+
+        site_temp.downloadContent("content.json", download_files=False)
+        site_temp.needFile("data/optional.any.iso.piecemap.msgpack")
+
+        with Spy.Spy(Peer, "getFile") as requests:
+            for i in range(10):
+                site_temp.needFile("%s|%s-%s" % (inner_path, i * 1024 * 1024, (i + 1) * 1024 * 1024))
+
+        assert len(requests) == 10
+        for i in range(10):
+            assert requests[i][0] == site_temp.peers["Peer:%s" % i]  # Every part should be requested from piece owner peer
+
+    def testDownloadStats(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        # Init source server
+        site.connection_server = file_server
+        file_server.sites[site.address] = site
+
+        # Init client server
+        client = ConnectionServer("127.0.0.1", 1545)
+        site_temp.connection_server = client
+        site_temp.addPeer("127.0.0.1", 1544)
+
+        # Download site
+        site_temp.download(blind_includes=True).join(timeout=5)
+
+        # Open virtual file
+        assert not site_temp.storage.isFile(inner_path)
+
+        # Check size before downloads
+        assert site_temp.settings["size"] < 10 * 1024 * 1024
+        assert site_temp.settings["optional_downloaded"] == 0
+        size_piecemap = site_temp.content_manager.getFileInfo(inner_path + ".piecemap.msgpack")["size"]
+        size_bigfile = site_temp.content_manager.getFileInfo(inner_path)["size"]
+
+        with site_temp.storage.openBigfile(inner_path) as f:
+            assert not "\0" in f.read(1024)
+            assert site_temp.settings["optional_downloaded"] == size_piecemap + size_bigfile
+
+        with site_temp.storage.openBigfile(inner_path) as f:
+            # Don't count twice
+            assert not "\0" in f.read(1024)
+            assert site_temp.settings["optional_downloaded"] == size_piecemap + size_bigfile
+
+            # Add second block
+            assert not "\0" in f.read(1024 * 1024)
+            assert site_temp.settings["optional_downloaded"] == size_piecemap + size_bigfile
+
+
+    def testPrebuffer(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        # Init source server
+        site.connection_server = file_server
+        file_server.sites[site.address] = site
+
+        # Init client server
+        client = ConnectionServer("127.0.0.1", 1545)
+        site_temp.connection_server = client
+        site_temp.addPeer("127.0.0.1", 1544)
+
+        # Download site
+        site_temp.download(blind_includes=True).join(timeout=5)
+
+        # Open virtual file
+        assert not site_temp.storage.isFile(inner_path)
+
+        with site_temp.storage.openBigfile(inner_path, prebuffer=1024 * 1024 * 2) as f:
+            with Spy.Spy(FileRequest, "route") as requests:
+                f.seek(5 * 1024 * 1024)
+                assert f.read(7) == "Test524"
+            # assert len(requests) == 3  # 1x piecemap + 1x getpiecefield + 1x for pieces
+            assert len([task for task in site_temp.worker_manager.tasks if task["inner_path"].startswith(inner_path)]) == 2
+
+            time.sleep(0.5)  # Wait prebuffer download
+
+            sha512 = site.content_manager.getFileInfo(inner_path)["sha512"]
+            assert site_temp.storage.piecefields[sha512].tostring() == "0000011100"
+
+            # No prebuffer beyond end of the file
+            f.seek(9 * 1024 * 1024)
+            assert "\0" not in f.read(7)
+
+            assert len([task for task in site_temp.worker_manager.tasks if task["inner_path"].startswith(inner_path)]) == 0
+
+    def testDownloadAllPieces(self, file_server, site, site_temp):
+        inner_path = self.createBigfile(site)
+
+        # Init source server
+        site.connection_server = file_server
+        file_server.sites[site.address] = site
+
+        # Init client server
+        client = ConnectionServer("127.0.0.1", 1545)
+        site_temp.connection_server = client
+        site_temp.addPeer("127.0.0.1", 1544)
+
+        # Download site
+        site_temp.download(blind_includes=True).join(timeout=5)
+
+        # Open virtual file
+        assert not site_temp.storage.isFile(inner_path)
+
+        with Spy.Spy(FileRequest, "route") as requests:
+            site_temp.needFile("%s|all" % inner_path)
+
+        assert len(requests) == 12  # piecemap.msgpack, getPiecefields, 10 x piece
+
+        # Don't re-download already got pieces
+        with Spy.Spy(FileRequest, "route") as requests:
+            site_temp.needFile("%s|all" % inner_path)
+
+        assert len(requests) == 0
diff --git a/plugins/BigFile/Test/conftest.py b/plugins/BigFile/Test/conftest.py
new file mode 100644
index 00000000..8c1df5b2
--- /dev/null
+++ b/plugins/BigFile/Test/conftest.py
@@ -0,0 +1 @@
+from src.Test.conftest import *
\ No newline at end of file
diff --git a/plugins/BigFile/Test/pytest.ini b/plugins/BigFile/Test/pytest.ini
new file mode 100644
index 00000000..d09210d1
--- /dev/null
+++ b/plugins/BigFile/Test/pytest.ini
@@ -0,0 +1,5 @@
+[pytest]
+python_files = Test*.py
+addopts = -rsxX -v --durations=6
+markers =
+    webtest: mark a test as a webtest.
\ No newline at end of file
diff --git a/plugins/BigFile/__init__.py b/plugins/BigFile/__init__.py
new file mode 100644
index 00000000..005d6661
--- /dev/null
+++ b/plugins/BigFile/__init__.py
@@ -0,0 +1,2 @@
+import BigfilePlugin
+from BigfilePiecefield import BigfilePiecefield, BigfilePiecefieldPacked
\ No newline at end of file