Command to reduce the filesystem size?

[Jagadesh]

Dear All;

To reduce the LV size we user lvreduce.
Is there any similar command to reduce the file system size.

command similar to lvreduce.
Thanks

[Mohanasundaram_1]

Hi Jagadesh,

There is no command to reduce filesystem.

If you are trying to reduce the LV, be prepared to do a newfs on the reduced LV and restore the data from a backup.

When you perform lvreduce, the command does not check if there is data in the extent it is removing, Therefore it may result in data loss.

Supported method is,

1) Backup filesystem
2) Lvreduce the LV
3) Newfs LV
4) Restore the backup

Hope this helps.

With regards,
Mohan.

[Steven E. Protter]

Don't try and reduce too much. If you try and lvreduce down to the last extent the commmand could fail, leaving you with no filesystem at all.

A backup is always a good idea. I wasn't aware that newfs was necessary. If you're careful you might not need to do that.

SEP

[Lee Tae-kyung]

Hi^^..

File system is a attribute. so, File system don't have the command of reduce or extend.

Good day~~

[Geoff Wild]

With Online JFS, you can reduce on the fly with fsadm.

fsadm -b M /mountpoint
lvreduce -L

Rgds...Geoff

[Mohanasundaram_1]

Hi Jagadesh,

(And Steve),This is what you can find in the man pages of lvreduce "warnings" section,

LVM does not store any information about which physical extents within
a logical volume contain useful data; therefore, reducing the space
allocated to a logical volume without doing a prior backup of the data
could lead to the loss of useful data. The lvreduce command on a
logical volume containing a file system of greater length than the
size being reduced to will cause data corruption.

To reduce a logical volume being used for swap, that swap area must
not be currently in use.

[Sunil Sharma_1]

Hi,

If you are using Veritas Volume manager you can use vxassist to do this.

In lvm if you have Online Jfs you can use fsadm.

No other way to reduce FS without lossing data.

Sunil