NFS problem

[S. Johnson]

Hi Darin,

Thanks for responding...
At 12:31 10/02/03 -0400, you wrote:
>what OS are your nfs clients running? there are know problems between 
>solaris and redhat 7.x and some 6.x. i did quite a bit of research into 
>this back in january for a grid cluster i was putting together, check out 
>this post. http://runlevelzero.net/pipermail/warewulf/2003-January/000100.html


My server and one client are Redhat 8.0, kernel version 2.4, the other 
client is Redhat 7.2, but still has a 2.4 kernel.



>are you getting any errors like "kernel: nfs: task 2752 can't get a 
>request slot"? i saw errors like this when i ran into nfs problems, the 
>nfs server was solaris with linux clients in this instance.

Those errors look very close to the ones I was seeing.  I did not write 
them down, unfortunately, but I know they had "request slot" in the message.

Thanks for your input.

Sean Johnson


>S. Johnson wrote:
>>I have 2 client systems that need to access a mail volume via NFS.  I 
>>believe it is an optimization/setup problem, but am unsure of what to try 
>>to resolve it.  Here's the setup:
>>Server 3 - NFS Server, redhat 8.0, exporting /users from a fiber channel 
>>array it hosts.  Mail is sent to and picked up to users home directories, 
>>so there is a lot of disk access happening with read and writes (4500 
>>users).  /etc/exports looks like this:
>>/db     192.168.1.0/255.255.255.0(rw,no_root_squash)
>>/isp    192.168.1.0/255.255.255.0(rw,no_root_squash)
>>/users  192.168.1.0/255.255.255.0(rw,no_root_squash)
>>For now, the main export I am concerned with is /users, however, all 
>>these partitions are on the same fiber channel raid and are still 
>>accessed by the clients.  Traffic on the other two shares in pretty 
>>minimal, but may still be a factor in overall performance of the system.
>>Servers 1 and 2 are configured to be able to run Postfix or courier-imap, 
>>and access the /users share from server 3 via NFS.  Here is the 
>>/etc/fstab the clients use:
>>server3:/db    /db    nfs bg,nfsvers=3,rsize=8192,wsize=8192 0 0
>>server3:/isp   /isp   nfs bg,nfsvers=3,rsize=8192,wsize=8192 0 0
>>server3:/users /users nfs bg,nfsvers=3,rsize=8192,wsize=8192 0 0
>>Servers 1 and 2 are able to mount and read the volumes fine when there is 
>>little or no traffic.  However, when you move either Postfix or 
>>Courier-imap services over to them, they eventually (after several hours) 
>>start to have NFS problems.  After a while, there will be hundreds of 
>>dead processes still hanging around and the load average skyrockets (200 
>>or more).  The mounts to /users or the other two are not 
>>available.  Executing a df or mount command hangs your terminal.
>>Sometimes you can kill off processes and restart NFS services, other 
>>times it requires a reboot of the client and usually means doing it by 
>>powering off the machine because it hangs on the NFS processes and will 
>>not shut them down.
>>Is there a tried and true way to setup NFS between the server and clients 
>>that will support high volumes of traffic?  If anyone knows of a better 
>>way to setup things the client and/or server side, please let me know.
>>Thanks,
>>Sean Johnson
>>
>
>
>--
>Darin Perusich
>Unix Systems Administrator
>Cognigen Corp.
>darinper at cognigencorp.com
>