Gareth:

Do you mean Veritas Volume Replicator (VVR)?  Volume Manager (VVM)  is
only the local storage virtualization piece of the Veritas product
suite.  You *can* use straight volume manager to replicate across
SANs, but I would hesitate from using it over long distances.  Here's
why:

VVM allows you to mirror any hardware that the server can see, so if
you have a good WAN with remote SAN storage that you see over IP, then
you could mirror "local" and "remote" disks with straight VVM.  But
performance will never be better than your "remote" disks.

With VVR, there are options available as to how current you want the
remote disks kept.  You can choose fully synchronous, but you can also
choose slightly degraded modes that will not slow down your local
server with waiting for remote writes.  (writes are cached locally and
sent across the wire as bandwidth permits)

So it really depends on how far away the remote server is.

And unless you have a Veritas Cluster (yet more software), you will
not be able to SEE the remote disks from a remote server.  The remote
disks will be marked as "in use" by the local machine, and VVM will
not mount them on the remote server until the disk group is deported
from the local server and imported to the remote one.

Having said all that, I love VVM for storage virtualization, VVR is a
pretty good product for remote replication, but needs to be set up and
tuned, and I have no experience with Veritas Cluster Manager (yet....)

Your other option is hardware replication, which most of the big
players offer.  Same issues apply.

Cheers,
--Kent
=================================
Kent Smith * IPSO Incorporated
Business * Technology * Solutions
Financial Services and Accounting Systems Consulting

http://www.ipsoinc.com

Thanks Kent,

Sorry, I did mean Veritas Volume Replicator.

I've been told that I need Volume Manager and VVR. Is this correct?

I've also been told that Id would be able to mount the mirrored disk on the
remote server where I could use it as a read only database (for reporting
purposes). Do you know if this would work? It seems a little far fetched to
me!

I envisaged the remote server being used as a reporting server until
disaster strikes when we would use it as a "minumum service" server until we
could get the production box back up and running.

Has anyone got or seen this kind of setup?

Thanks for any replies...

Gareth

-----Original Message-----
From: Kent Smith [mailto:ksmith@ipsoinc.com]
Sent: Wednesday, December 17, 2003 8:17 PM
To: info-ingres@ams.org
Subject: Re: ingres + veritas volume manager

Gareth:

Do you mean Veritas Volume Replicator (VVR)?  Volume Manager (VVM)  is
only the local storage virtualization piece of the Veritas product
suite.  You *can* use straight volume manager to replicate across
SANs, but I would hesitate from using it over long distances.  Here's
why:

VVM allows you to mirror any hardware that the server can see, so if
you have a good WAN with remote SAN storage that you see over IP, then
you could mirror "local" and "remote" disks with straight VVM.  But
performance will never be better than your "remote" disks.

With VVR, there are options available as to how current you want the
remote disks kept.  You can choose fully synchronous, but you can also
choose slightly degraded modes that will not slow down your local
server with waiting for remote writes.  (writes are cached locally and
sent across the wire as bandwidth permits)

So it really depends on how far away the remote server is.

And unless you have a Veritas Cluster (yet more software), you will
not be able to SEE the remote disks from a remote server.  The remote
disks will be marked as "in use" by the local machine, and VVM will
not mount them on the remote server until the disk group is deported
from the local server and imported to the remote one.

Having said all that, I love VVM for storage virtualization, VVR is a
pretty good product for remote replication, but needs to be set up and
tuned, and I have no experience with Veritas Cluster Manager (yet....)

Your other option is hardware replication, which most of the big
players offer.  Same issues apply.

Cheers,
--Kent
=================================
Kent Smith * IPSO Incorporated
Business * Technology * Solutions
Financial Services and Accounting Systems Consulting

http://www.ipsoinc.com
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