Migrate OS to new disks

[Verónica Muñoz Segovia]

Hello!

I'm planning to migrate the vg00 filesystems to a new disk and then make a mirror of that disk.

Righ now the vg00 is in a 9Gb disk and I don't have more space in order to increase some filesystems.

I want to move all the vg00 to a 18Gb disk and then create a mirror with another 18Gb disk.

I would like to know some ideas to can do this, because a have never something similar.

I was thinking to create an Ignite tape in order to migrate all the vg00 to the new disk.

Can I create with a 9Gb disk a mirror with an 18Gb disk? or can I copy the disk with the dd comand?

Please, I hope somebody could help me because I know this is quit delicated and I don't have much time to do it.

Thanks in advance

Veronica

[Patrick Wallek]

You could use ignite to do what you want to do. If using ignite the steps would be:

1) Create the make_recovery tape
2) Shutdown machine and remove 9GB and install 18GB disks
3) Restart machine and boot from Ignite tape
4) Interrupt the ignite boot so that you can modify the system parameters, specifically your vg00 configuration.
5) Let ignite do the install. And you should be back up and running a 2-4 hours.

There is another method you can use that Peggy Fong has posted 2 or 3 times. Here is a link to a thread that Peggy posted this procedure to. Her procedure could work for you as well.
http://forums.itrc.hp.com/cm/QuestionAnswer/1,1150,0xa1c6d06ed8c8d4118fef0090279cd0f9,00.html

[Ajitkumar Rane]

You can create a mirror of the 9gb to the 18gb and then remove the 9gb once you feel you r safe to continue on the new 18gb root disk.
I think this could be one of the best ways other than ignite, to do it without much of down time.
You need to use the command lines for root disk mirroring.

The procedure is given in the System Administration task manual in chpt 7. check it on the hp site

Goodluck.

[Verónica Muñoz Segovia]

Thanks for your response.

I have some doubts,

1. I don't want to remove the disk until the second can be up and working, and then can reuse this one. Am I going to have some problems with boot path? If so, what am I do in order to avoid this?

2. What kind of system parameters am I need to considerated (I don't want to miss nothing)?

3. Do you know if Peggy solution apply with different disk sizes?

4. If I use dd or mirror software, is a problem the different disk sizes?

Sorry If I do a lot of questions

Thanks

Veronica.

[Verónica Muñoz Segovia]

This is another thing that I have to considerate for my unexperience in the beggining.

I was needing more space on /opt and /var and what I did (so stupid) was create a 7Gb LUN on my AutoRAID 12h to extend /opt and /var. The server K370 10.20 is working fine but I want to correct my mistake, that's why I was thinking in ignite because I know create a recovery tape of the entire vg00.

What happen with mirror, makes a mirror of the disk or vg00?

Thanks

Veronica.

[Ajitkumar Rane]

with the mirror UX, you do not have to worry as long as the new disks size 18gb is greater than the old disk 9gb.It will work.Also since the data on the new disk after mirroring would be exact replica you dont even have to worry about any changes to the data.Once you feel the system is ok after mirroring you can then remove the disk as said earlier.
Once done you will have to change the boot path, in the stable storage, you can do it online with the setboot command.
with Mirroring its upto you to decide which lvols you want to mirror.its the lvextend -m 1 /dev/vg00/lvolx /dev/dsk/new command which you issue for each lvol.But it would be foolish not to mirror not to mirror the whole VG00.

I did not understand you second input about repairing you mistake. Do you want to reduce the size of /opt and /var or do you want these to go to the new disk as the size is, then mirroring is the option.
If you want to change the sizes that is reduce the lvols while changing to the new disk then I think ignite tape is the solution.

Good luck

[Les Schuettpelz]

Dave Fargo using Les's ITRC account...

Let's make a best-case assumption, you have OnlineJFS available, and all vg00 filesystems are JFS except /stand which is hfs.

Also, you don't want the machine to be down, and you want to increase the vg00 filesystems for future needs, including possibly 11.X upgrade which will use more space.

I'm not as up-to-speed with ignite as much of the civilized world, perhaps. I personally like the 'pvmove' command for migrating data online, the extend-new-mirror and drop-old-mirror operation does the same thing, but requires 2 commands where pvmove does it in 1. Also, even if you don't have MirrorUX, you always have pvmove.

Either way, you need to watch your lvlnboot info, it can get confused along the way and may need to be redone. After you pvcreate and mkboot the 18Gb drive, you can pvmove the vg00 lvols 1 at a time to the new disk.

Do /stand first, then you can unmount it and lvextend/extendfs it to the new size before remounting (/stand is not normally in use on the running system).

Assuming your primary swap is lvol2, you can pvmove it next. Ideally, you won't need to increase this. I am not sure if it is wise to lvextend it while it is in use, perhaps someone else can comment on this. An option would be to allocate a dummy lvol on the new disk to reserve the contiguous extents, and later remove the dummy lvol to lvextend the swap lvol during a planned outage.

Then, pvmove the rest of the lvols in order. With OnlineJFS, each one can be lvextended and fsadm'd to the new size after it is moved, to keep thing contiguous. Without OnlineJFS, you could again use dummy lvols to reserve contiguous extents if you want to increase these 'neatly' the next time you go to init 1.

[Patrick Wallek]

The problem you will have if you add the 18GB drive to VG00 and then mirror your current set up from the 9GB drive is that your Max PE per PV for VG00 is probably incorrect. The effect of this is that you will only see 1/2 of your 18GB drive since there are not enough physical extents available to see the whole physical volume.

Unless you were thinking ahead when you set up VG00 for the 9GB drive, it was only set up to see a 9GB drive. There is NO way to change the value of Max PE per PV without rebuilding VG00. To rebuild VG00 you can use the Ignite/UX (make_recovery) method, or Peggy Fongs method.

[Verónica Muñoz Segovia]

When I said my mystake I'm referring, that in the beggining I had all vg00 in a particular disk, people here ask me to increase /opt and /var but I didn't have enought space on the same disk where vg00 was resident. So, what I did was create a LUN on the AutoRAID 12h, this is like a new logical disk, a partition on the same array where database is resident, and that partition I assigned to vg00 to can extend /opt and /var, physically a part of /opt and /var are not on the same dispositive or in the same physical disk but logicaly yes because that partition of the array belongs to vg00.

Maybe this answer is works that the previous but I hope you can understand me.

And I have OnlineJFS and MirrorUX.

[Edward Finneran]

The max pe per pv issue is a probably a killer for the easiest way to move, which is just mirroring across, since you won't be able to use all the space on the new drive.

Otherwise, the make_recovery is one way to do it. We have found various problems over the years with make_recovery not putting things exactly back the way they started if you do an interactive restore. But...what you can is do a preview of what the make_recovery is going to do, and then manually tweak the file so that it does an automated recovery when you actually boot it. This way, if you want your filesystems to be a different size, and restore onto the 18GB drive instead of the 9, you can do it all in one shot.