2005-01-20 16:38:18

by Tobias Diedrich

[permalink] [raw]
Subject: NFSv3, 2.6, ext3 and dir_index

Hi,

I recently switched from a local homedir to a NFS mounted homedir
and noticed some strange things:

I have a Cronjob that goes over my mp3 directory and after the
switch find would print "foo/bar/blubb: No such file or directory"
for a few (approx. 2-3 out of 1928) directories, but not always the same
ones. Also, my mp3 player program would sometimes stop short in the
middle of a song and skip to the next one, because it got ENOENT on
a read of an open file.

Now first I thought it might just be a problem with my Kernel
version or one of the patches I'm using and upgraded to a more
recent one (currently 2.6.10-ac8-nfsacl on the client and
2.6.10-ac8-imq-nfsacl on the server, I also had the same problem
without the nfsacl patches).

Then I read an older thread about trouble with ext3/dir_index and
NFS in older 2.6 versions and tried disabling dir_index (Which was
enabled on all my ext3 filesystems). With that the problem
vanished.

Are there any known problems with dir_index and NFS, or is this
maybe a new bug?

Getting a tcpdump of the client<->server traffic proved difficult,
because it is a quite sporadic bug and reproducing it would involve
quite a lot of NFS traffic. I could reliably trigger this with my
CD/DVD burning script, which generates md5sums for each file and
puts them both into the file MD5SUMS in the current directory, as
well as into another file in my Homedir (But the files being
md5summed also live on another NFS export, so there is a _lot_ of
traffic).

I _do_ have a traffic capture of ls returning "No such file or
directory" on the current directory, then cding up a level, down into the
directory again and then a working ls.

Client fstab entry:
nukunuku:/mnt/space1/ranma /home/ranma nfs hard,intr,bg,udp,rsize=4096,wsize=4096 0 0

/proc/mounts entry:
nukunuku:/mnt/space1/ranma /home/ranma nfs rw,v3,rsize=4096,wsize=4096,hard,intr,udp,lock,addr=nukunuku 0 0

Server export file:
/ melchior.yamamaya.is-a-geek.org(sync,rw,no_root_squash)
/mnt/space1 melchior.yamamaya.is-a-geek.org(sync,rw,no_root_squash)
/mnt/space2 melchior.yamamaya.is-a-geek.org(sync,rw,no_root_squash)
/mnt/space3 melchior.yamamaya.is-a-geek.org(sync,rw,no_root_squash)

--
Tobias PGP: http://9ac7e0bc.uguu.de


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2005-03-14 17:22:45

by Chip Salzenberg

[permalink] [raw]
Subject: Re: NFSv3, 2.6, ext3 and dir_index

According to Tobias Diedrich:
> Are there any known problems with dir_index and NFS, or is this
> maybe a new bug?

Did you ever get any replies on dir_index vs. nfs?

I'm just setting up a new server and I'm wondering if there's
something still out there that might make me sorry to use dir_index.
--
Chip Salzenberg - a.k.a. - <[email protected]>
Open Source is not an excuse to write fun code
then leave the actual work to others.


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