topic Removing Logical Volume in Operating System - HP-UX

Removing Logical Volume

Cliff Lim Kok Hwee — Fri, 09 Sep 2005 02:58:04 GMT

Gd Day Forumers,

I need to mirror an existing lv and once mirror would like to remove the original copy.

New harddisk: /dev/rdsk/c8t5d6

Original copy: /dev/vg30/lvol1 residing in /dev/dsk/c7t5d0

I will be doing the following steps:
1)vgextend /dev/vg30 /dev/dsk/c8t5d6
2)lvextend -m 1 /dev/vg30/lvol1 /dev/rdsk/c8t5d6
3)lvreduce -m 0 /dev/vg30/lvol1 /dev/dsk/c7t5d0

Query: Will there be any impact to my above mentioned steps?

Thanks/cliff

Re: Removing Logical Volume

Devender Khatana — Fri, 09 Sep 2005 03:02:01 GMT

Hi,

There should not be any impact except that the access will be quite slow if you intend to do it online and either of two disks are in use.

HTH,
Devender

Re: Removing Logical Volume

Sunil Sharma_1 — Fri, 09 Sep 2005 03:04:40 GMT

Cliff,

I think you want to remove old disk. You can use pvmove command. First add new disk to same Volume grou and then use pvmove command.

#pvmove

Sunil

Re: Removing Logical Volume

Cliff Lim Kok Hwee — Fri, 09 Sep 2005 03:05:11 GMT

Hi Deva,

Will it be locking the primary harddisk while i try to perform lvreduce if it is writing to primary harddisk?

Thanks/cliff

Re: Removing Logical Volume

Cliff Lim Kok Hwee — Fri, 09 Sep 2005 03:07:56 GMT

Hi Sunil,

I need to keep existing data onto new disks. Therefore pvremove will not be appropriate.

Correct?cliff

Re: Removing Logical Volume

Devender Khatana — Fri, 09 Sep 2005 03:07:57 GMT

Hi,

No it does not lock any of the disks and read/writes to both will happen normally. The only impact will be slow performace as stated earlier.

Sunil,

pvmove will move all PE's of the disk to new disk which is not the intention here.

HTH,
Devender

Re: Removing Logical Volume

Devender Khatana — Fri, 09 Sep 2005 03:11:16 GMT

Hi,

If you want to remove the old disk having copy all its data to new disk then pvmove is the single command to achive that.

It is pvmove not pvremove. "man pvmove" for details.

It will be also run if you simple reduce the VG from the old disk after extending to the new disk.

HTH,
Devender

Re: Removing Logical Volume

Cliff Lim Kok Hwee — Fri, 09 Sep 2005 03:12:28 GMT

Hi Forumers,

Am I right to presume my mentioned steps are correct?

Thanks/cliff :)

Re: Removing Logical Volume

Devender Khatana — Fri, 09 Sep 2005 03:14:22 GMT

Hi,

Yes the steps are correct. You can go ahead.

HTH,
Devender

Re: Removing Logical Volume

morganelan — Fri, 09 Sep 2005 03:16:52 GMT

I think you must using /dev/dsk/c8t5d6, not /dev/rdsk/c8t5d6 in lvextend command.I think after this, your commands are correct.

Re: Removing Logical Volume

Adisuria Wangsadinata_1 — Fri, 09 Sep 2005 03:23:06 GMT

Hi Cliff,

You wanna move /dev/vg30/lvol1 from c7t5d0 into c8t5d6 with mirror, right ?

You can do the steps that wrote above, but the best way if there's no activity running on /dev/vg30/lvol1 when you want to lvreduce the one on c7t5d0 (either on the low peak or you shutdown the application that using this lvol).

The good way to do it if you have a downtime slot for it and make sure you have also a good backup.

Hope this information can help you.

Cheers,
AW

Re: Removing Logical Volume

Cliff Lim Kok Hwee — Fri, 09 Sep 2005 03:28:31 GMT

Yes guys,

Thanks for highlighting the EXTRA "r" in rdsk

You wanna move /dev/vg30/lvol1 from c7t5d0 into c8t5d6 with mirror, right ? YES correct.

Thanks/cliff :)