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XP-256 Disaster Recovery Issue

Chris Bishop
Occasional Advisor

XP-256 Disaster Recovery Issue

We recently purchased an XP-256 storage array, and I had planned to use it in conjunction with make_recovery for disaster recovery. I have mirrored internal boot disks which I plan on using for the operating system and vg00, and I want to use make_recovery to create a bootable tape to recover the vg00 volume group in the event of a disaster. Everything else I want to put on the XP-256 and connect it via fibre channel or scsi. In the event of a disaster on the box, I was hoping to replace the box with hardware that has the same architecture, then boot from my make recovery tape to restore the vg00 volume group. I was thinking that connecting the box back to the XP-256 at this time would make those luns readily accessible to the new box. Recently, I have heard that there is a problem with this plan. I have heard that LVM uses an algorthym that incorporates the serial number of the processor for each box, therefore, a new box would not be able to see those LDevs that were made available to the old box. This does not sound correct to me, because it would render make_recovery useless in any LVM setup. Please comment and clarify this issue for me.
2 REPLIES
Dave Wherry
Esteemed Contributor

Re: XP-256 Disaster Recovery Issue

Chris,
I've never heard of that serial number stuff. Not to say it's not real, it just doesn't make sense.
It was my understanding that you could just move the cable from one host to another, vgimport and the volume groups/data would be available on the new host. I've actually done this with an EMC.
In your scenario, the LVM information would be restored onto the new host via make_recovery so the vgimport would not be needed.
I think your plan would work, just can't say for sure.
I might be able to do some testing with this in the next couple of weeks. I have a box that is supposed to free up for me early next week. If I have time I'll try it and see what happens.
Matt Walls
Advisor

Re: XP-256 Disaster Recovery Issue

As long as you have map files, and created them useing vgexport -s, you should be fine. Most likely you will have to vgimport -s on a new server. and you may see a message regarding the system id. however, this is perfectly ok, and you can ignore it. all you need to do is a vgcfgbackup.

We do this kind of stuff all the time.

let me know if you have further questions.
Matt