topic Re: NFS filesystem testing issue, in Operating System - HP-UX

NFS filesystem testing issue,

Becke — Wed, 01 Dec 2010 11:54:57 GMT

Team

We have an NFS filesystem which is successfully exported and mounted to it's clients...

However application team has performed a test and requested us to unexport the filesystem on it's server while it is mounted on clients, I have commented out fs in /etc/exports directory and then I have forced umounted it,

in doing the above nfs on clients becomes unavailable obviously and df hung, this also impacts nfs client servers performance due to nfs not available ?

Any idea on how to over come this issue?

what attributes I may need to change if that ?

It is only exported as v4 on server.

below are nfs attributes on client

/client_nfs nfs4 Dec 01 18:17 rw,bg,soft,intr,retry=1,retrans=1,timeo=1,vers=4,sec=sys

Re: NFS filesystem testing issue,

amipankaj — Wed, 01 Dec 2010 12:12:11 GMT

Hi Raf,

Thats not the right way to unexport the nfs. Anyway, now you need a reboot of client server to fix this issue.

Good Luck.
Pankaj

Re: NFS filesystem testing issue,

R.O. — Wed, 01 Dec 2010 12:49:32 GMT

Hi,

I would export the FS again, and check it is available on clients again. Unmount it on clients and unexport it again when there are no clients remaining mounting it.

Regards,

Re: NFS filesystem testing issue,

Larry Klasmier — Wed, 01 Dec 2010 22:03:41 GMT

I agree with RO. This may or may not work, however, the chance of it working definately out ways having to reboot, which the only alternative.

Re: NFS filesystem testing issue,

Patrick Wallek — Wed, 01 Dec 2010 22:30:00 GMT

>>in doing the above nfs on clients becomes
>>unavailable obviously and df hung, this also
>>impacts nfs client servers performance due
>>to nfs not available ?

Of course. If the directory exported on the NFS server isn't available nothing will work.

>>Any idea on how to over come this issue?

Don't unexport and unmout on the NFS server!

I'm confused as to what exactly you are trying to accomplish here. If the directory on the NFS server disappears (unmounted, unexported, etc.) then of course your clients will start having problems, especially if they access the NFS mount point regularly.

I'm confused as to what exactly you are looking for from us.

Re: NFS filesystem testing issue,

Becke — Thu, 02 Dec 2010 11:25:35 GMT

Thanks Patrick

I'd agree with you if nfs server is unavailable then ofcourse clients will have problems. In this case business isn't getting impacted enough as it is a test environment and in build phase.

However I just wanted to find out if nfs server is unavailable due to an outage or crashes in prod then if there is an alternate method to avoid slow response time so it won't impact client's application.

By the way I have said the same stuff to my apps team that what would you expect if you bring nfs server down and expects everything robust on client then it may not be possible.

Appreciate everyone's help and input here.
We have a great team

Thanks

Re: NFS filesystem testing issue,

Ismail Azad — Thu, 02 Dec 2010 16:51:29 GMT

Hi raf,

Reading your last post... the following information might help. Remember, NFS is a single point of failure if used in the traditional sense. Hence, you would at times need to consider something called as "client side failover" wherein if your NFS server is unavailable as you said, you would still have another server which would allow you to mount the same filesystem as a client. It is because NFS is an SPOF, we have the concept of a highly available NFS. Since, you are revolving around the point of an SPOF, the preceding alternatives might be useful.

Regards
Ismail Azad