mirror disk

[kestens jan]

Hi,

I have a system containing four identical disks. First two disks (c0t6d0 and c0t5d0)
are in use (vg00). My question is can I mirror these two disks (vg00)to the two remaining disks with the MirrorDisk software.


Regards,

Jan K

[Sandip Ghosh]

Yes you can do that. First you have to extend the volume group with the other two disks and then do the mirroring lvextend -m.

Sandip

[A. Clay Stephenson · Accepted solution]

If you have two unused disks then yes. You do a vgextend to add these two disks to vg00 anf then do an lvextend -m 1 to mirror each logical volume. Max vgextend and lvextend for details. If you want to mirror boot drives you have to do a bit more:

Let's assume that your mirror boot disk is c1t6d0 and that your additional disk is c1t5d0




pvcreate -f -B /dev/rdsk/c1t6d0
vgextend /dev/vg00/ /dev/dsk/c1t6d0

mkboot /dev/rdsk/c1t6d0
mkboot -a "hpux -lq (;0)/stand/vmunix" /dev/dsk/c1t6d0

pvcreate -f /dev/rdsk/c1t5d0
vgextend /dev/vg00 /dev/dsk/c1t5d0

You then do an lvextend for EACH lvol and specify the desired destination disk. /stand, primary swap, and / (lvols 1 thru 3 MUST go on the mirror boot disk)

e.g.
lvextend -m 1 /dev/vg00/lvol1 /dev/dsk/c1t6d0
...
...
lvextend -m 1 /dev/vg00/lvol8 /dev/dsk/c1t5d0


I would also run the same mkboot -a command on your original boot disk so that you can boot off either disk without quorum. NOTE: To get the full benefits of mirroring so that a cable/controller faiure controller can be tolerated, you should mirror your two disks to two drives on another controller.

[harry d brown jr]

Jan,

Mirroring is done at the Logical Volume (filesystem) level and not at the "disk" level, and you choose what you want mirrored, by using Clay's examples, logical volume by logical volume.

live free or die
harry

[pap]

Hi,
You can definately do mirroring depending upon the disk availaibility.
As you have free disks available you can do as per Clay's procedure. It will be a good idea to confirm that the disks are not containing any data in it. Then you can proceed with following command.

pvcreate -B -f /dev/rdsk/cxtydz

-f option will not warn you before erasing everything on that disk. So be cautious.

One more thing, while doing mirroring using lvextend -m 1 .......command, do it in a sequence.....stand , root.....etc..
It is best to do pvdisplay -v on your original root disk and not down the sequence of logical volumes and then proceed for mirroring....

Good luck.

-Piyush.