AIX

Hi,

need advice on this.

Is it possible to assign a mountpoint from a SAN storage to server1 & server2.
Use NFS to the same mountpoint from server2 so that concurrent access is allowed.
Can this setup be used together with HACMP?
If server1 crash, the mountpoint resource will swing to server2, will it automatically remove the NFS and server2 take over the mountpoint resource and become active.

Simpler approach is to use PFSS?

Any ideas?

Regards
Solo

My answers right after your questions.

1) Server A and B both are assigned same VG from SAN storage.

ANS: This is possible but then only one of them can have exclusive access. I think you could use concurrent VG, not too sure if that works with HACMP, that forms another cluster.

2) Server A takes possession of resources /TEST and is active (HACMP)

ANS: I would keep the share on another server if you have one OR a NAS share.

3) Server B using NFS shares the /TEST from Server A.

ANS: That is possible. Don't put the entries in /etc/filesystems but manually mount it as part of a cluster start script

Cluster WAS Application (active:active) in Server A & B concurrently writes to /TEST.

4) When Server A crashes or goes offline, HACMP auto swing resources /TEST over to Server B and becomes active.

ANS: This /TEST filesystem must be in the /etc/filesystems and the cluster start script must export it as soon as it gets access to the VG and mounted it.

Server B NFS connection to Server A is lost when Server A becomes offline but empty mountpoint remains. When HACMP swing resources over (same mountpoint name), will there be problems?

ANS: That could be a problem. Why don't you mount the filesystem with a different name and then link it to a specific directory for WAS to write ?.

Make the vg jfs2 enhanced concurrent and auto mount it on both.
Then they can both write to it what ever happens to the other system, HA or not.

dukessd, Are you talking to automount over NFS ? If not, can you please explain the procedure ? or a document link so that I can update myself .

thanks, Kaps

No. Forget NFS.
When you create the vg make it JFS2 enhanced concurrent.
Zone the SAN disks to both systems.
Search the IBM HA docs for JFS2 enhanced concurrent.

I did read about this one. This is what I understood,

1. A normal concurrent VG does not support filesystems ( applications will need to manage their storage on raw LVs).

2. Enhanced concurrent mode supports filesystems and the VG to be varried on on a set of systems. BUT The HACMP and LVM work together to put a lock , so that only one system can perform write operations to a filesystem from this concurrent VG.

Correct me , or direct me to a better reading.

Regards,

Kaps