[Users] NFS stall problem

[Cedric Jeanneret]

Hello,

we're currently using openvz (2.6.18-128.2.1.el5.028stab064.4) on debian lenny nodes, with debian lenny or etch VE (kernel was alienized from latest openvz rpm).

We have an nfs server on a hardware node (so NOT in a VE) which shares some cartographic datas (means: LOT of small files, aka tiles).

For now, we're mounting NFS shares in VE in this way :
nfs-server:/path/to/share on /path/to/mount/point type nfs (ro,nfsvers=3,rsize=32768,wsize=32768,hard,proto=tcp,timeo=600,retrans=2,sec=sys,addr=nfs-server)

Share is done as follow :
/path/to/share     IP(ro,all_squash,anongid=65534,sync,no_subtree_check)

Problem :
sometimes (well, about once a day, or each two days), nfs share seems to be stalled. That means :
- unable to access datas from VE
- unable to umount share in VE

The only thing we can do is a restart of the VE.
As far as I can see, the others VE having an nfs share on the same HN don't have any problem (well, for a while, than it stalls too).

We don't have any logs in syslog nor kern.log, either on HN or in VEs.

NFS-SRV is in a VLAN, and distributes files accross up to 3 VLANS. firewall rules are correct...


Any idea ?

I've read on wiki that "it's better to mount nfs share on HN, then use a mount -o bind". We can't afford that, as we need to move VE quiet often, and this without shutting them down (vzmigrate --online)... 

Thank you in advance.

Best regards,

C.
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