NFS problem

[Justin Bennett]

I don't do nfs mounts that way, I mount my nfs vols using automounter. I 
don't have any greif, but I don't have that many users, only about 200. 
Automouter wil lexpire mounts and unmount them when not being used.What 
os is on servers 1 and 2. Possible NFS version conflict? I used to have 
some greif with NFS when mounting shares on a solaris intel box from a 
linux box.



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
>

-- 
Justin Bennett
Network Administrator
RHCE (Redhat Certified Linux Engineer)
Dynabrade, Inc.
8989 Sheridan Dr.
Clarence, NY 14031