lvm extend on running file system

drManhattan · 11-12-2011, 10:55 AM

Hi

I wonder can I extend file system and lvm volume on running server.
File system is being used when I want to extend its size.

Can I do this without any danger to file system itself ?

ths for help.

catkin · 11-12-2011, 11:58 AM

LVM volume: Yes. File system: depends on the file system.

No -- there is always a small possibility of something going wrong.

drManhattan · 11-13-2011, 10:58 AM

I have ext3 fs.

How can I do it without downtime ?

hen770 · 11-13-2011, 11:16 AM

The fs itself couldn't be resized when it's mounted and in use, take full backup if you try to force it, but in case it fails you have more downtime, so better to do do it unmounted.

drManhattan · 11-13-2011, 01:05 PM

thx for info.

But if I perform fs extension while fs is mounted but there is no I/O operations ?

syg00 · 11-13-2011, 04:51 PM

Not (necessarily) true.
Ext3 has supported online resize for some time (years). Extending the f/s can be done online, is supported, and works (for me). Check "man resize2fs".

A backup is always prudent.

hen770 · 11-15-2011, 04:02 AM

Yep, my mistake there, you can resize you ext3 or ext4 fs with resize2fs (as long as the kernel supports it [from the man page]).
I have did it today with my /root ext4 partition that was on a 10G logical volume but the fs itself was just 7G, so with the /root partition mounted as root I have used resize2fs /dev/mapper/system-root (my lv name), and it became 10G in 2 sec.