Changing 9GB mirror to 18GB. HPUX 10.20 on L Class server

[Phil1970]

Hi,
Could someone please explain the best way to extend a 9gb mirror group for a data volume. I've been asked to replace a mirror group that contains 2 x 9gb HDD's with 2 x 18gb HDD's. The data would then be restored to the new 18gb mirror set. I need some advice on the best way to complete this. Any advice (hopefully step by step) would be greatly appreciated. Many thanks in advance.

[Jaime Bolanos Rojas.]

Newphil, I was not around for 10.20.

But if you are using lvm, I would do a vgexport and then a vgimport when that is done, I would extend the vg on the new drive.

Regards,

jaime.

[Robert-Jan Goossens]

please post the output of "vgdisplay -v /dev/vgxx" and what kind of backup you are using.

Regards,
Robert-Jan

[A. Clay Stephenson]

Almost certainly you can't because unless special provisions were made when the VG was created, it is sized to contain the largest physical disk listed. Almost certainly, if you try to do a vgextend then you are going to only be able use 9GiB of your 18GiB disks. This means that you will probably have to create a new VG and then copy the data from the old to the new. It also gets more complicated if this a a boot VG.


The first step is to do a "vgdisplay -v /dev/vgXX" where XX is the desired VG and post that data. That data will determine your next steps. You should also indicate if you can physically attach all 4 disks simultaneously.




And 10.20 on an L-box, I don't think so.

[DCE · Accepted solution]

If the existing volume group will accept 18GB disks (it may only use 9GB of the 18 GB, depending on the parameters used to create the VG)

add the disks to the VG.
extend a second mirror to one of the 18 GB disks
remove one of mirrors to the 9 GB disks
mirror to the second 18 GB disk
remove the mirror from the last 9 GB disk

If you have to create a new VG to accomodate the 18 GB disks size

create the new vg
create the new lvol's
mount the new lvols to temporary mount points
copy the data over
umount all the mount points
change the entries in /etc/fstab to point to the new lvols and mount everything

or

mount the lvols on the new disks to the correct mount points and restore your data from tape

[Steven E. Protter]

Shalom,

Break all the mirrors, extend the original lvols, destory the broken lvols, then re-mirror.

This gives you an automatic backout plan in case something goes wong.

SEP

[sathish kannan]

Hello NewPhil,

Check your "vgdisplay -v" of the volume group and check your maximum physical volume size. If it less than your new 18GB, then you will be wasting the new 18GB disk space.
Better to create a new Volume group and copy the data from old filesystem to new filesystem.

Regards
Sathish

[Phil1970]

Hi all,

Many thanks for all the very quick replies.

I'm in the process of collecting 'vg' and 'lvol' info as requested. I'm also confirming what backup solution they use. I'm hoping to have this information by tomorrow, Friday 21st July 2006 and will update this problem/question with any attachments as soon as I receive them. I will update this soon and point all replies.

Kind regards,
Phil

[Florian Heigl (new acc)]

The VG is being sized by the disks available upon creation, but defaults usually allow about twice the size of the largest volume.

so there is a high probability that the VG can accomodate 18GB disks while 36GB disks would be limited to like 17GB of usable space.

Once You have the VG information for us, we can tell for sure.

Florian

[Phil1970]

Hi all,

Very sorry for the delay in getting the vgdisplay info to you. I've put a request to the customer to supply these details but as yet have had no response. I have chased this over the last few days. Once they get fed up with 'pester power' I'll hopefully be able to attach all requested info. I'm hoping to update this thread towards the end of this week.

Many thanks.

[Phil1970]

Hi all,

This is my new HP Forums name (changed from Newphil).... I've finally got an update for this case!! Very sorry for the lengthy delay in getting this posted.

I've been chasing the customer for the last few weeks, I've visited the site today and have attached copies of the VGDISPLAY for VG01 & VG02. I've also attached the lvdisplays for these VG's. I've just noticed I've missed a few lvols (backup, history & live) from VG01. Used lvdisplay -v /dev/vg01/lvol* to get this info, hopefully this won't cause an issue.

The initial spec of an 9GB mirror was incorrect. They have two seperate 9GB disks, one for VG01 and one for VG02 with no mirror. They want to install 2 x 18GB drives and hopefully extend these VG/LVols as they are running at almost 100%. What would be the quickest, safest way to replace each of these 9GB disks and restore the data? (They use fBackup as the backup/restore program) Could I remove a 9GB, vgcfgrestore to the new 18GB and then lvextend? Then just restore the affected data to the new disk? I've got basic HPUX skills so It would be great to get a step by step solution. Many thanks in advance and once again sorry for the delay in this reply!

[Phil1970]

Vgdisplay output

[Phil1970]

lvdisplay for VG01 (lvdiaply for VG02 on last main message)

[DCE]

Since the the vg's were initally created with 9 GB disks, they probably will not fully utilize the 18 GB disks.

I would create a new vg that will use all of the space on the 18 GB disks (and even modify the vg parameters at creation time to allow for even bigger disks)

Then I would create all of the lvols in the size desired in the new vg.

perform a backup of the data

unmount the old lv's

mount the new lv,s and restore

OR

mount the new lv's to to temorary mount points
copy the info from the original lv's
unmount the original lv's
mount the new lv's to the original names

[Pete Randall]

As you can see from the vgdisplay output, the VG, as originally created, can only contain 9GB (PE size of 4 times MaxPE of 2171). In order to use the 18 GB disks, you will need to define a new VG (it might be a good idea to specify a larger PE size or MaxPE so this restriction won't exist should future expansion be required). The create the logical volumes and restore the data to them. See the man pages for vgcreate, lvcreate and newfs for further details.


Pete