topic Re: Mirror data in AutoRAID and SAN in Operating System - HP-UX

Mirror data in AutoRAID and SAN

yc_2 — Mon, 03 Jun 2002 02:58:43 GMT

Hi,

I'm planning to migrate data stored in AUTORAID disk to SAN (HDS).

Can I mirror the logical volume in AUTORAID to SAN or there is a better way to do it ?

Appreciate any advice,
YC

Re: Mirror data in AutoRAID and SAN

Michael Tully — Mon, 03 Jun 2002 03:09:28 GMT

Hi,

Mirroring would be a good choice providing
the LUN sizes your going to use are of
nearly equal size. Remember one of the
crucial rules of extending volume groups,
and that is that the disks being added
cannot be any bigger than the first disk
that was used to create the group. If it
is, that is all you will see. If this is
the case with you, you are perhaps better
off creating a new volume group with
different mount points, copying the data
and then re-mounting the filesystems on
the orginal mount point names.

HTH
~Michael~

Re: Mirror data in AutoRAID and SAN

harry d brown jr — Mon, 03 Jun 2002 14:10:07 GMT

YC,

It's no different that mirroring to another internal disk other than the speed in which mirroring will take place. The SAN disk should be much faster than the 12H so that shouldn't be an issue. Personally, I'd move everything off of the 12H and redeploy the 12H to another server that doesn't care about disk IO.

live free or die
harry

Re: Mirror data in AutoRAID and SAN

yc_2 — Mon, 03 Jun 2002 23:26:38 GMT

Hi,

Thanks for your valuable advice.

To migrate the data from AUTORAID to SAN in a graceful manner, should I perform:

1) mirror across to SAN
2) split the mirror
3) extend the VG if need be

Rgds,
YC

Re: Mirror data in AutoRAID and SAN

Michael Tully — Tue, 04 Jun 2002 00:58:42 GMT

Hi YC,

You could set up a mirror, and this would work fine, but consider what has been mentioned in the previous posting about volume group disk sizes. These rules apply when adding additional disks to existing volume groups.
You can't move a logical volume from one group to another, if your considering creating a new group and mirroring the existing logical volumes.

So in conclusion, if your disks fit into the existing volume group, go ahead and mirror and then reduce the mirror from you old disk,
do not do an lvsplit.

HTH
Michael