Mirror copy of Lun from one VA7400 to another

[Nikolai Korobeynikov]

Hello.
We have two-nodes ?????????????? under MC/ServiceGuard 11.12, two disk arrays va7400. One server is a database server, the second server is an application server. How can I make mirror copy of Lun from one va7400 to another through MirrorDisk/UX software.
Where can I find some info how to do it?

[RAC_1]

You have two arrays. Insteand of doing mirror copies through MirrorDisk, you can set raid level 0+1 to have mirror copies. This way the slight overhead will be avoided had you used MirrorDisk.

If you have to prepare mirror copies then put the disks from both arrays(preferably of same size) in volume group and you can do mirroring.

While creating logical volume or with lvextend.

Say you have disks c1t2d0(from array 1) and c2t2d1 (from array 2)
then lvextend -m 1 /dev/vg01/lvol1 /dev/dsk/c2t2d1

will create the mirror of c1t2d0(lvol1) on disk c2t2d1.

[Nikolai Korobeynikov]

Ok, I create Lun on the second va7400 the same size as in first va7400.

For example:
I have volume groupe vg31:
PV is /dev/dsk/c6t0d1 and /dev/dsk/c8t0d1 is alternate link.
I create Lun on the second va7400 and PV's are /dev/dsk/c6t2d2 and /dev/dsk/c8t2d2 is alternate link.
I do lvextend -m 1 /dev/vg31/lvol1 /dev/dsk/c6t2d2.

What happens with alternate link in description of vg31 in /etc/lvmtab?
Is this description will be lost or not?

[Eugeny Brychkov]

Dmitry, simply inspect lvmtab by issuing
strings /etc/lvmtab
If you set alternate links up for physcal volumes when you did create/extend volume group then these links should be seen in lvmtab in the same order you wrote them in the command line. You may wish to inspect vgdisplay also
vgdisplay -v /dev/vg31
Eugeny