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We've got a setup involving separate web & email servers mounting various shares on the same pysical NFSv3 server.

The web server uses a share for apache vhost files, the mailserver uses a share for user mail. (Maildir format, courier-imap)

The mailserver, suddenly and without warning, seems to be randomly 'locking up' due to the nfs share becoming unresponsive. 'df' hangs when it gets to the mounted nfs share. Any attempt to access the share from within the system effectively hangs the process.

The web server, so far - remains unaffected, so I'd like to think we can rule out issues on the NFS server. Both web & email use the same mount options, of which I've tried several combinations, to no avail. Sometimes it runs without issue for weeks, yet we just had it lock up less than 24 hours after increasing the amount of NFS threads on the server & remounting the shares.

Any comments or suggestions ?

rpcinfo output:

rpcinfo -p localhost

program vers proto   port
100000    2   tcp    111  portmapper
100000    2   udp    111  portmapper
100024    1   udp  32768  status
100024    1   tcp  60949  status
100021    1   udp  32769  nlockmgr
100021    3   udp  32769  nlockmgr
100021    4   udp  32769  nlockmgr
100021    1   tcp  41693  nlockmgr
100021    3   tcp  41693  nlockmgr
100021    4   tcp  41693  nlockmgr


rpcinfo -p $nfs_server

program vers proto   port
100000    2   tcp    111  portmapper
100000    2   udp    111  portmapper
100024    1   udp    752  status
100024    1   tcp    755  status
100011    1   udp    613  rquotad
100011    2   udp    613  rquotad
100011    1   tcp    616  rquotad
100011    2   tcp    616  rquotad
100003    2   udp   2049  nfs
100003    3   udp   2049  nfs
100003    4   udp   2049  nfs
100021    1   udp  37709  nlockmgr
100021    3   udp  37709  nlockmgr
100021    4   udp  37709  nlockmgr
100003    2   tcp   2049  nfs
100003    3   tcp   2049  nfs
100003    4   tcp   2049  nfs
100021    1   tcp  54549  nlockmgr
100021    3   tcp  54549  nlockmgr
100021    4   tcp  54549  nlockmgr
100005    1   udp    651  mountd
100005    1   tcp    654  mountd
100005    2   udp    651  mountd
100005    2   tcp    654  mountd
100005    3   udp    651  mountd
100005    3   tcp    654  mountd
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when it hangs can you do a ps -ef and send the output ? –  silviud Apr 27 '11 at 1:04
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1 Answer 1

In my experience. NFS is notorious for problems like this. Could it be related to a problem with your network switch?

Do the web server and mail server access the same NFS server? if not, try moving the NFS server for your email to a different network port and see if that helps.

Otherwise try some of these options in your fstab file. increase the timeouts. Set the soft option. You might also like to try the fsc (filesystem cache) option. I'm hoping that it will cache the write operation and solve your problem.

See: http://linux.die.net/man/5/nfs

On a side note, your web server is mostly reading. Your mail server is mostly performing writes.

If all that fails, I'd consider ditching nfs and using iSCSI instead.

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