Can we now shrink file systems with smit? 2

[rondebbs]

Hello, I have a p570 running aix 5.3. I have a VG called sasvg1 - 544GB. I have one LV (saslv1) and a file system called /sasfs1. The LV and file system are about 500GB but only 55GB are currently being used by the file system.

I would like to shrink the file system to 100GB. This would give me several hundred GB free space in the VG. I would then create a second LV and file system that would be around 300GB.

I beleive we can now shrink an online file system with 5.3. I have never done this although I have increased many file systems while they were up and running. I go to smit - Change/Show Characteristics of an Enhanced Journaled File System. I use the tab key to change the unit size to GBs. I then go to "number of units" and type +10 to increase the file system by 10GB.

Can I simply type -400 to shrink it? This is a 24/7 application. Can I shrink it while users are logged on? If needed I could probably get an outage. My biggest concern is that I don't want to hose something.

VOLUME GROUP: sasvg1 VG IDENTIFIER: 00cda5cf00004c0000000000291aa747
VG STATE: active PP SIZE: 256 megabyte(s)
VG PERMISSION: read/write TOTAL PPs: 2125 (544000 megabytes)
MAX LVs: 256 FREE PPs: 2 (512 megabytes)
LVs: 3 USED PPs: 2123 (543488 megabytes)
OPEN LVs: 2 QUORUM: 2
TOTAL PVs: 3 VG DESCRIPTORS: 3
STALE PVs: 0 STALE PPs: 0
ACTIVE PVs: 3 AUTO ON: yes
MAX PPs per VG: 32512
MAX PPs per PV: 1016 MAX PVs: 32
LTG size (Dynamic): 256 kilobyte(s) AUTO SYNC: no
HOT SPARE: no BB POLICY: relocatable
root@wfssas01/#

 

[khalidaaa]

All you need to do is this:

chfs -a size=-400G /sasfs1

You can do this while the users are using the same without affecting any thing (though i guess it might take some time so be patient)!

Regards,
Khalid

 

[khalidaaa]

Almost missed one very important thing! You can only do this if your filesystem is jfs2 (on AIX 5.3 as you are already)!

Regards,
Khalid

 

[Eddyliu]

That's right!

 

[p5wizard]

As you state that it is an Enhanced JFS, that's OK - is the same as JFS2.

I wouldn't think twice about doing that kind of stuff online. However it is a big chunk you want to take out. The system might complain that it doesn't have enough "free" space to reduce the FS in one go, online, for 400GB. I once had the same problem and had to move some big files around inside the FS to "create" free space (contiguous enough for shrinkfs to cooperate...


HTH,

p5wizard

 

[khalidaaa]

I didn't see the "Enhanced" part

Regards,
Khalid