topic Re: Reducing logical volume... in Operating System - HP-UX

Reducing logical volume...

DC. — Mon, 28 Jan 2008 15:05:51 GMT

Dear HP-UX gurus,
Would really appreciate your advice the steps to reduce a size of logical volume:

Before some time, i was try to reduce logical volume, at that time it gone corrupted.
I have to reduce one logical volume again. can you please suggest what should i do from first. note that i haven't such a time for backup and restoration. and no extra space to copy that data.

hope to hear from you. looking forward for your awaiting reply.

Thanks
Piyush

Re: Reducing logical volume...

Geoff Wild — Mon, 28 Jan 2008 15:21:08 GMT

First thing you do - ensure you have a good backup.

Then, with Online JFS:

fsadm -b M /mountpoint
lvreduce -L /dev/vgXX/lvolX

Example - decrease /tmp from 2GB to 1GB

fsadm -b 1024M /tmp
lvreduce -L 1024 /dev/vg00/lvol4

Rgds...Geoff

Re: Reducing logical volume...

Steven E. Protter — Mon, 28 Jan 2008 15:24:59 GMT

Shalom Piyush,

To do this at all, you need Online JFS, otherwise your only option is to back up the data, remove the logical volume, rebuild and restore.

There are good instructions on how to use fsadm to do what you wish in the first post.

Caveat. If you try and reduce too much, this can lead to failure and data corruption.

Always take a full backup prior to reduction.

SEP

Re: Reducing logical volume...

James R. Ferguson — Mon, 28 Jan 2008 15:27:25 GMT

Hi:

The key is to reduce the size of the _filesystem_ contained within the logical volume, first.

If you don't have OnlineJFS (and I hope you do), then you must backup the filesystem; 'lvreduce' (or 'lvremoved and 'lvcreate') the logical volume; 'newfs' the filesystem and reload the data from the backup.

If you have OnlineJFS, use 'fsadm' to reduce the size of the filesystem; THEN use 'lvreduce' to reduce the corresponding size of the container --- the logical volume.

See the manpages for more information.

Regards!

...JRF...

Re: Reducing logical volume...

Hasan Atasoy — Mon, 28 Jan 2008 15:41:42 GMT

hi piyush ;

it is not possible without online jfs.

HasanÃ§

Re: Reducing logical volume...

Tim Nelson — Mon, 28 Jan 2008 15:46:12 GMT

If using online JFS you need to also run the defrag before executing any reductions. read man fsadm_vxfs ( dD and eE options )

As mentioned it is much safer to create a new smaller FS, move your data, then delete the old one. ( or send the data to tape, delete and recreate the smaller and restore ).

Re: Reducing logical volume...

Bill Hassell — Mon, 28 Jan 2008 19:01:50 GMT

You cannot reduce the size of a logical volume that has a filesystem without the optional product called Online JFS. IF you do not have this product installed, you will have to purchase the product , then you can follow the advice above using fsadm. Check for this product with:

swlist -l product OnlineJFS

There is no other way to reduce a filesystem without a backup and restore.

Re: Reducing logical volume...

Bill Hassell — Mon, 28 Jan 2008 19:06:49 GMT