dd an OS disk from a 36GB disk to a 72GB disk

[Alzhy]

Has anyone done this? Will the OS be able to boot off the 72GB disk? And any probable issues?

[A. Clay Stephenson]

It should be bootable because I have definitely dd'ed when the source and destination disks are equal in size. I assume that you are going to do this from the /dev/rdsk/cXtYdo level as opposed to lvol by lvol because that will not work. Of course, the remaining space will be unusable. My one reservation is that the boot firmware might not be able to recognize a 73GB disk.

[Alzhy]

A. Clay, thanks.

I too have been dd'ing from like drives for purposes ranging from DR to rapid cloning of systems. But I have not done any dd from a small disk to a bigger disk yet and thought to ask this esteemed forum.

I do have a recipe of cloning a boot disk properly and doing dd's of the individual rlvols but I do prefer whole disk copies if it is at all possible.

I will try and I will let you know after this weekend.

[TwoProc · Accepted solution]

Nelson,

I've done the smaller to bigger dd OS copy. It worked fine for me. You'll have trouble in trying to use the rest of the space however (if that is a concern). The main problem would be that the vgroup will have max pe per volume is set too low to use the rest of the disk. I've seen in other postings that there exists an unsupported tool to fix that. The way to do begin is to get that disk mounted on another running system (vgexport/vgimport), and then attempt your doctoring of the disk & vg from there.

[Alzhy]

Messr. Joubert, you cleared my head.. for our LVM managed bootdisks this will certainly be a "problem" -- the idea with the 73Gs was to actually be able to use the rest of the 73GB disk. So I gues I will ditch the DD aproach and just settle for the other approach to clone LVM bootdisks on an lvol per lvol bases (either using dd or dump/restore).

However, for our VxVM managed bootdisks.. I see no issue.

[Geoff Wild]

What about using the good old trusty tool "ignite" - and just ignite your 36GB, swap it out with a 72GB, and ignite recover to the 72?

Rgds...Geoff

[Mark Greene_1]

What hardware? We just put a pair of 72GB drives in our 7410 and them moved the non-OS lvols to that, so while not exactly what you are doing, the system does work with the 72GB drives with no problems.

mark

[DCE]

Nelson,

Why not an Ignite restore? If you use a make_net/tape_recovery image to "restore" to the larger disk, you will have the option of increasing the maxpe so you will be able to utilize all of the larger disk.

[Alzhy]

Ignite will not work for us coz the idea is actually for DR. We will be offsiting copies of our running OS periodically. And we do not have a spare server to do ignite recovers to. With us moving to VxVM managed bootdisks - I think this will be less of an issue. Besides, we already have a recipe of an LVM based OS clone solution that will fit our needs.

[TwoProc]

Nelson, I agree with Geoff.

Use Ignite restore to recreate the 36G system on the 73G disk (it's very flexible and simple ). During the restore, you'll be able to lay out the formerly 36G OS on your 73G drive AND you all of the space on the 73G any way you'd like. THEN, dd the new 73G disk image to every other 73G drive you have. This would give you what you're going for, with only one intermediate step.

Keep in mind that the ignite restore process is built just exactly for what you're trying to do. That is (among other things), to have a flexible restoration system for replacement of a new root disk - regardless of whether or not the new disk is exactly the same size.