P.s. I think I need to clarify this:
I am only reading from the mounts, and not modifying anything on the
server. and so the commonest causes on stale file handles do not appy.
Anirban
On Thursday 19 December 2013 01:16 AM, Chalcogen wrote:
Hi everybody,
A few months back I joined a project where people want to replace
their legacy fuse-based (twin-server) replicated file-system with
GlusterFS. They also have a high-availability NFS server code tagged
with the kernel NFSD that they would wish to retain (the
nfs-kernel-server, I mean). The reason they wish to retain the kernel
NFS and not use the NFS server that comes with GlusterFS is mainly
because there's this bit of code that allows NFS IP's to be migrated
from one host server to the other in the case that one happens to go
down, and tweaks on the export server configuration allow the
file-handles to remain identical on the new host server.
The solution was to mount gluster volumes using the mount.glusterfs
native client program and then export the directories over the kernel
NFS server. This seems to work most of the time, but on rare
occasions, 'stale file handle' is reported off certain clients, which
really puts a damper over the 'high-availability' thing. After
suitably instrumenting the nfsd/fuse code in the kernel, it seems that
decoding of the file-handle fails on the server because the inode
record corresponding to the nodeid in the handle cannot be looked up.
Combining this with the fact that a second attempt by the client to
execute lookup on the same file passes, one might suspect that the
problem is identical to what many people attempting to export fuse
mounts over the kernel's NFS server are facing; viz, fuse 'forgets'
the inode records thereby causing ilookup5() to fail. Miklos and other
fuse developers/hackers would point towards '-o noforget' while
mounting their fuse file-systems.
I tried passing '-o noforget' to mount.glusterfs, but it does not
seem to recognize it. Could somebody help me out with the correct
syntax to pass noforget to gluster volumes? Or, something we could
pass to glusterfs that would instruct fuse to allocate a bigger cache
for our inodes?
Additionally, should you think that something else might be behind our
problems, please do let me know.
Here's my configuration:
Linux kernel version: 2.6.34.12
GlusterFS versionn: 3.4.0
nfs.disable option for volumes: OFF on all volumes
Thanks a lot for your time!
Anirban
P.s. I found quite a few pages on the web that admonish users that
GlusterFS is not compatible with the kernel NFS server, but do not
really give much detail. Is this one of the reasons for saying so?
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