Re: Writing to an NFS share truncates files on >8Tb Raid + LVM2

[Ramon van Alteren <ramon@vanalteren.nl>]

Ramon van Alteren wrote:

> I'd like to report a situation which looks like a bug in the kernelbased
> nfs server implementation.
>
> Based on responses from a different mailinglist and google I tried unfsd
>  the userspace nfsd implementation which appears to work fine (still
> testing) The above test-case works for both loopback and remote 
> mounted filesystems.
>
> I'm not on the list so please CC me.

unfsd appears to suffer from the same problem only it has a higher 
treshold for them to appear.
We're seeing the same behaviour with larger files created.

for i in `seq 1 10`; do dd count=400000 bs=1024 if=/dev/zero 
of=/root/test-tools/test.tst; ls -lha /root/test-tools/test.tst ; rm 
/root/test-tools/test.tst ; done

400000+0 records in
400000+0 records out
dd: closing output file `/root/test-tools/test.tst': No space left on device
-rw-r--r--  1 root root 328K Feb 22 09:53 /root/test-tools/test.tst
400000+0 records in
400000+0 records out
dd: closing output file `/root/test-tools/test.tst': No space left on device
-rw-r--r--  1 root root 176K Feb 22 09:53 /root/test-tools/test.tst
400000+0 records in
400000+0 records out
dd: closing output file `/root/test-tools/test.tst': No space left on device
-rw-r--r--  1 root root 168K Feb 22 09:53 /root/test-tools/test.tst
400000+0 records in
400000+0 records out
dd: closing output file `/root/test-tools/test.tst': No space left on device
-rw-r--r--  1 root root 176K Feb 22 09:53 /root/test-tools/test.tst

A test with the same command directly onto the local filesystem runs 
without problems.

for i in `seq 1 10`; do dd count=400000 bs=1024 if=/dev/zero 
of=/data/bonnie++/test.tst; ls -la /data/bonnie++/test.tst ; rm 
/data/bonnie++/test.tst ; done
400000+0 records in
400000+0 records out
-rw-r--r--  1 root root 409600000 Feb 22 09:59 /data/bonnie++/test.tst
400000+0 records in
400000+0 records out
-rw-r--r--  1 root root 409600000 Feb 22 09:59 /data/bonnie++/test.tst
400000+0 records in
400000+0 records out
-rw-r--r--  1 root root 409600000 Feb 22 09:59 /data/bonnie++/test.tst
400000+0 records in
400000+0 records out
-rw-r--r--  1 root root 409600000 Feb 22 09:59 /data/bonnie++/test.tst
400000+0 records in
400000+0 records out
-rw-r--r--  1 root root 409600000 Feb 22 10:00 /data/bonnie++/test.tst

Any help would be much appreciated.

Based on a comment from Lee Revell, I can reproduce the same behaviour 
with both sync & async options set on the nfs server (kernel and userspace)

Regards,

Ramon

-- 
To be stupid and selfish and to have good health are the three requirements for happiness, though if stupidity is lacking, the others are useless.

Gustave Flaubert