SAN disks share NFS with failover server

[sgreyling]

We have BL860 servers running HPUX 11.31 hostname ecmqprd1 that has direct access to SAN disks. From this server I NFS the SAN filesystem /data to another 6 BL860 servers.
I now want to setup another separate server that also has direct access to the SAN to be a failover for the ecmqprd1 server if it ever should go down.

Basically if ecmqprd1 go down, the separate server should then NFS /data to the current 6 servers.

Will this be possible at all?

[Viktor Balogh]

> Will this be possible at all?

Yes, it is. The easiest method would be to use ServiceGuard with it's HA-NFS extension, which was made for this very purpose. If you don't have a license for SG, then this task will get to a massive scripting task.

How would you want to accomplish high-availability? Do you have a clustering solution installed?

[sgreyling]

Unfortunately we dont have a license for Service Gaurd and neither do we have a cluster environment.

At the moment when I access the SAN disks from the second server I have setup for failover, I do not see the data that is currently on the disk.

How will I create/mount /data on the failover server for it to access the same data under /data?

[Viktor Balogh]

> How will I create/mount /data on the failover server for it to access the same data under /data?

this is the hard part... you could mount it in read-only mode, but I am certain that you want r/w access.

You should implement a mechanism that mounts it in r/w mode either on server1 or server2. --> that's with self-made scripts

You also need a floating IP for this, similar how serviceguard works, and the nfs server will listen on that floating IP. If server1 fails, all this thing should be started on server2. (import vg, mount fs, set up floating ip, start nfsd on floating ip)


The question is, do you want to have r/w access to that share?

If not, you can mount it on both servers in read-only mode, and export it from both servers as ro.

[Alzhy]

What "SAN" array do you have?

Maybe it has NFS Services available which could be "cheaper" than having a HA-NFS solution?

If your BL860 acting as NFS Server is solely doing NFS Serving and nothing else -- that to me - that is a major architectural flaw as there are other solutions to provide robust NFS more cost effectively to wit:

1) explore your SAN Array if it has NFS capabilities
2) look at NAS appliances that are specifically tuned for file serving (NFS, etc) duties
3) deploy LINUX for file serving duties.

[sgreyling]

Hi all,

Yes, we do need read/write access to the SAN at all times. We figured that since we do not have Service Guard, we will do a manual failover if the PRD server should die. This might not be high availablity but at least we have a secondary for backup.
So basiclly I need the TST server to access the same data as what the PRD server can access. At the moment I can see the disks, but when I mount /data I do not see the data.

We have the EMC Clariion (CX4-480) SAN

Not sure if this has NFS services.

I can deploy a Linux server on a BL460. How will I then go about doing NFS thru Linux?

Regards,
Schalk

[Viktor Balogh]

> At the moment I can see the disks, but when I mount /data I do not see the data.

what is the volume manager used on hp-ux? LVM or VxVM?

> I can deploy a Linux server on a BL460. How will I then go about doing NFS thru Linux?

If you are using VxVM and if you have initialized the disks with the CDS format, you will be able to read that filesystem on linux. I think that the HP-UX LVM is not compatible with LVM on Linux, so that is not an option.

[Alzhy · Accepted solution]

"I can deploy a Linux server on a BL460. How will I then go about doing NFS thru Linux?"

My good sir -- NFS is part and parcel of practically every Linux OS just like UNIX. Actually most NFS / Fileserver Apl;iances and NAS use LINUX as the operating system. Your BL860 relegated to just NFS serving duties is an utter waste of its power - not to mention costs.

How do you set up NFS Serving on Linux? Quite the same as on UNIX sir. Set up your Filesystem and export it... RHEL 5.x uses the /etc/exports style of NFS exports control and it is rather easy.

Now if you want Highly Available NFS Serving -- you can do so with RHCS with NFS as a HIghly available service. It works exactly like NFS-HA on HP-UX using ServiceGuard but without the $$ for licenses.