topic mirroring two VA7400 in Disk Enclosures

mirroring two VA7400

ziad_1 — Wed, 25 Jun 2003 11:29:56 GMT

I have one VA7400 as a shared storage in a cluster environment (2 x rp7400 , 2 x fiber switches, one VA7400 .... ) .Can I add another VA7400 "that contains the same amount of disks" to the share storage and configure it as a mirror for the current VA7400 (to have full redundancy for the entire VA7400)? ( I suppose that The mirror for all the logical volume will be handled by the LVM in HP-UX and it needs additional configuration in the cluster files).
If yes it will be grateful if I can discuss the steps to be performed).thanks in advance for your reply.

Re: mirroring two VA7400

Leif Halvarsson_2 — Wed, 25 Jun 2003 12:55:59 GMT

Hi,
Yes, of course it is possible to use software mirroring for RAID volumes, just as for ordinary physical disks. From HP-UX point of view there is no difference with a RAID volume or a physical disk. But a rather expensive solution. You need to install the Mirror UX product (it is licensed).

Re: mirroring two VA7400

ziad_1 — Wed, 25 Jun 2003 13:17:51 GMT

thanks for your prompt reply

Re: mirroring two VA7400

Eugeny Brychkov — Wed, 25 Jun 2003 16:09:52 GMT

This is good solution if you're building campus SAN topology - one server and VA are in one physical location (London) and another server and VA is in another (Paris). In case or earthquake (god forbids) one of your nodes will be up with one of VAs.
If you do not build this kind of redundancy level topology then it's no need to mirror one VA to another. VA is high available system, built on different RAID levels (autoraid mode) to improve reliability/availability and perfomance, having redundant controllers and can be configured to have redundant paths etc.
It's not wise to build software raid over hardware one. The only important action you should take regularly is to review VA's state (armdsp -a) and its logs (armlog -e) and check if VA is healthy. If there will be any failed components or suspicious events I would call HP for assistance... you know even very very highly redundant system can crash if you'll not notice (multiple) component failures in time!
Eugeny

Re: mirroring two VA7400

Peter Mattei — Thu, 26 Jun 2003 07:53:15 GMT

Ziad

What you are thinking of is a very good and HP supported solution! It' called "HP Extended Campus Cluster"
See http://h71028.www7.hp.com/HP/render/1,1001,5918-6-100-225-1,00.htm and ftp://ftp.hp.com/pub/enterprise/extended_campus_cluster.pdf
We do have some customers doing exactly that!

I suggest you invite your local HP team to support or do the implementation. They also know the supported levels and needed patches of HP-UX, ServiceGuard, MirrorUX and the VA7400.
Attached are the 3 possible configurations and an example of an installation here in Switzerland.

Cheers
Peter