NFS problem

[S. Johnson]

Hi Justin,

At 11:39 10/02/03 -0400, you wrote:
>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.

I am not sure this would be a good option, given that the volume I am 
sharing has 4500+ users constantly getting and checking mail.  This share 
would have constant RW I/O.  What does automounter use to connect the systems?

>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.


All boxes are Redhat Linux.  Servers 2 and 3 are Redhat 8.0, server one is 
Redhat 7.2 and is getting reloaded with 8.0 today.  They should all support 
version 3 on the 2.4 kernel.

Thanks,

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