Alan,
I have installed and config'd Service Guard a few times. The data disks are
shared between systems with an exclusive "lock" which guarantees that only 1
node can access the shared disks at a time. The locking mechanism is LVM
based. Specifically, only certified HP disks support the locking. Since
the Netapps is an NFS Server, it is outside the scope of LVM and would not
play well in a SG environment. NFS locks are 'advisory' - my process hopes
your process adheres to pre-extablished rules.
Netapps has cluster configs which allow for redundancy of the filer and its
DASD. This alone would be redundancy of DASD, where SG attempts to
eliminate ALL single points of failure.
Another potential issue. NFS clients (HP-UX included) are not usually happy
when the NFS server hangs, panics,...
I worked on a SG environment where each node in the cluster was both a NFS
client and NFS server to the other nodes. This sort of became a nightmare
to implement.
HP has an NFS Toolkit for Service Guard which supports ONLY an NFS server,
not the client.
On the other hand (the non-supported hand ;>) ), if you configured SG
properly, the adoptive node (adopting the application during failover) would
do an NFS mount to the filer and be able to access the data, if it were not
corrupted. If you do decide to go ahead with this unsupported environment,
I would be very interested in hearing the results.
Dave Mills
Cypress Systems
-----Original Message-----
From: Alan Beauchemin [mailto:Alan.Beauchemin.B@bayer.com]
Sent: Thursday, March 30, 2000 8:22 AM
To: - *toasters(a)mathworks.com
Subject: NetApp and HP MC Service Guard
I have a project involving four HP systems requiring continuous
availability. I
would like to use MC Service Guard but I am not sure if I can use this
software
with a NetApp. Is anyone using this failover software in a NetApp / HP
environment? I would also be curious of other methods of high availability
from
the server side with a NetApp?
Thanks
Alan