diff --git a/remotefilelog/remotefilelog.py b/remotefilelog/remotefilelog.py
--- a/remotefilelog/remotefilelog.py
+++ b/remotefilelog/remotefilelog.py
@@ -17,6 +17,10 @@
 from mercurial import filelog, revlog, mdiff, ancestor, error
 from mercurial.i18n import _
 
+# corresponds to uncompressed length of revlog's indexformatng (2 gigs, 4-byte
+# signed integer)
+_maxentrysize = 0x7fffffff
+
 class remotefilelognodemap(object):
     def __init__(self, filename, store):
         self._filename = filename
@@ -118,6 +122,12 @@
 
         meta, metaoffset = filelog.parsemeta(text)
         rawtext, validatehash = self._processflags(text, flags, 'write')
+
+        if len(rawtext) > _maxentrysize:
+            raise revlog.RevlogError(
+                _("%s: size of %d bytes exceeds maximum size of 2GiB")
+                % (self.filename, len(rawtext)))
+
         return self.addrawrevision(rawtext, transaction, linknode, p1, p2,
                                    node, flags, cachedelta,
                                    _metatuple=(meta, metaoffset))