Reduce file system?

[Greg Stark_1]

Hi all,
I have a 1 Gig vxfs filesystem that I would like to reduce to 50 MB. I'm not sure how to do this, but I think I would do the following:

umount /mnt/bi
lvreduce -L 50 /dev/vg01/datalvol1
mount /dev/vg01/datalvol1 /mnt/bi

When I run the lvreduce command, it says I will corrupt the file system. Is this expected, or am I way off?

Thanks again,
Greg

[harry d brown jr]

If you only need 50mb, I'm assuming you can easily backup anything on that LV. So back it up. Delete it, recreate it, then restore your data.


live free or die
harry

[Uday_S_Ankolekar]

Hi,

This thread would give you more detail
http://us-support.external.hp.com/cki/bin/doc.pl/sid=c1a5179a1d766fcd51/screen=ckiDisplayDocument?docId=200000024631672

Goodluck
-USA..

[G. Vrijhoeven]

Hi,

i agree with harry. just backup and recreate.
Your problem might be caused by files that are in the file system. (bdf)

Gideon

[James R. Ferguson]

Hi:

Unless you have Online JFS, shrinking a filesystem requires that your reload its data after performing a 'newfs' on the filesystem following the 'lvreduce' of the logical volume.

If you have Online JFS, you *may* be able to shrink the filesystem without rebuilding it and reloading its data. Reduction will fail, however, if inuse blocks reside within the area to be returned. Defragmentation (via 'fsadm') sometimes moves and frees sufficient space and improves the success rate.

Regards!

...JRF...

[Darrell Allen]

Hi Greg,

lvreduce will not maintain the integrity of a file system. Basically you are simply slicing off a chunk of disk space (quite a large chunk in your case) without regard for what was in the space that you are removing. With online JFS and using fsadm you have a chance for success but there's no guarantee it will work. You can forget about it working shrinking from 1GB to 50MB.

Always make a backup before adjusting the size of filesystems and logical volumes anyway, especially when shrinking. Simply reload it. No headaches!

Darrell

[Deshpande Prashant]

HI
Since you want to reduce it so small, try considering removing and recreating the LV and File system.
Backup the file system.
umount /mnt/bi
lvremove /dev/vg01/datalvol1
lvcreate -L 50 /dev/vg01/datalvol1
mkfs -F vxfs /dev/vg01/data1vol1
mount /dev/vg01/datalvol1 /mnt/bi
Restore the data.

Take a look at following discussion, for using fsadm to reduce file system with online JFS .

http://forums.itrc.hp.com/cm/QuestionAnswer/1,11866,0x3b07c7af36b7d5118ff10090279cd0f9,00.html

Thanks.
Prashant.

[Bernie Vande Griend]

Unless you're using Online JFS, lvreduce will corrupt the data on the filesystem unless you are very likely. A reduction of this size will certainly mess up the data.
You must back up the data first and then either lvreduce it or do a lvremove/lvcreate again.

[Greg Stark_1]

Here's what I did:

# fsadm -F vxfs -d -D -e -E /mnt/db
# fsadm -F vxfs -b 51200 /mnt/db

but got the following error:

fsadm: cannot shrink /dev/vg01/rdatalvol1 - upgraded fs - inodes are currently
in use.

Not sure what it means, but ended up deleting/re-creating. Thanks for all your help.
Greg

[Uday_S_Ankolekar]

Hi,

Umount the mount point first..did you..?

[Greg Stark_1]

Yes, I tried it first without unmounting, then with, but got a different error, something about not a root inode.

[James R. Ferguson]

Hi Greg:

The failure to be able to dynamically reduce the VxFS filesystem has been commonly reported with Online JFS versions up to 3.3.

If you quiesce all utilization of the filesystem, and defragment first, then *sometimes* you can shrink. Online JFS version 3.3 is said to address the common failure to be able to shrink filesystems.

Regards!

...JRF...

[Greg Stark_1]

Any idea how to tell what version of Online JFS you are on? I have tried:
swlist -l product
swlist -l fileset
swlist -l bundle
but none seems to show what version.

[James R. Ferguson · Accepted solution]

Hi Greg:

Online JFS 3.3 utilizes a runtime license mechanism.

The product number for JFS 3.3 is B3929CA for servers and B5118CA for workstations on 11.0. JFS 3.3 comes with 11i.

The product number for JFS 3.1 is B3929BA.

Regards!

...JRF...