topic Storage migration in Operating System - HP-UX

Storage migration

PSS SYS ADMIN — Tue, 01 Oct 2002 14:49:29 GMT

Hi everyone,
I have an N4000 connected via 2 fibre channel to a EMC Symmetrix. Now we have a new Simmetrix.
I want to move the vg of the db to the new storage.
There's an existing procedure to do it without any risk?

Regards...
PSS

Re: Storage migration

James R. Ferguson — Tue, 01 Oct 2002 14:58:14 GMT

Hi:

If you have MirrorDisk/UX you can use it to perform your data migration with a minimum of downtime.

Move one of your two fibre connections to the new Symmetrix leaving one for the old SAN.

Create mirrors of your logical volumes on the new SAN; sync the mirrors; and sever the old mirror copies from the old SAN.

Finally, move the remaining old fibre connection from the old to the new SAN and add the associated device files as alternate (pv) links (since I am presuming that you have two fibre channels representing primary and alternate LVM links).

Regards!

...JRF...

Re: Storage migration

Craig Rants — Tue, 01 Oct 2002 15:00:41 GMT

Are the both symmetrix hooked up right now? What about some type of symmir split? EMC should be able to provide these services or advice for this type of thing, especially if you bought a new array.

GL,
C

Re: Storage migration

Vincent Fleming — Tue, 01 Oct 2002 15:17:29 GMT

If you have SRDF, you can use that to migrate the data; or I understand that EMC will issue temporary licenses for SRDF as part of a service to migrate your data for you.

The least expensive means of migrating the data is to use Mirror/UX, if you have it.

Good luck!

Re: Storage migration

Sanjay_6 — Tue, 01 Oct 2002 16:38:50 GMT

Hi,

As James is suggesting, connect both the EMC's to the system, extend the existing VG on the old EMC to include the pv's (luns') on the new EMC and mirror the data. Then reduce the Luns from the old emc and you have all your vg and data on the new EMC.

Hope this helps.

Regds

Re: Storage migration

Jordan Bean — Wed, 02 Oct 2002 04:37:41 GMT

If the new hypervolumes are identical in size, then you can use either SRDF or LVM mirroring to walk the volume groups over to the new Symm.

But be careful if the new hypervolumes are not identical in size. You will not be able to use SRDF. You may be able to use LVM mirroring to accomplish online migration if the volumes are smaller. However, if they are larger and the volume group's Max PE will not accomodate them, then you may have to use a new volume group... which complicates matters. I've done this almost regularly between a 3430 and a 8430 where the hypervolumes differ by 68 meg.

Also, if you use PowerPath, then you must deconfigure the paths that will be moving to the new Symm.

Re: Storage migration

Animesh Chakraborty — Wed, 02 Oct 2002 05:06:22 GMT

Hi,
EMC did it for us.
They used SRDF for data transfer.It is very safe method.
I will advise to get EMC professional service for this migration.

Re: Storage migration

Tom Geudens — Wed, 02 Oct 2002 05:17:28 GMT

Hi,
All the above answers are correct. However, there is a way to do this without downtime ... and the trick is pvmove. I would do this as follows :
1. I presume you are using alternate links (since you have two connections ?). vgreduce the volumegroups (removing the alternate link) so you can disconnect one of the connections.
2. Connect the new Symmetrix to the available connection. ioscan will make the devices available.
3. vgextend the volumegroups with devices from the new Symmetrix.
4. pvmove the old devices to the new devices
5. vgreduce the old devices (that are now empty, be sure to check that !) from the volumegroups and disconnect the second "old" link.
6. Connect the second link to the Symmetrix
7. ioscan will make the alternate devices available. vgextend the volumegroups with the alternate devices.

Hope this helps
Tom