Should I upgrade ZFS from v15 to v28?

[pixies]

Hi there,

If it is the wrong forum, please move the post. 10x!

I've just upgraded my NAS from FreeNAS 0.7.2 to NAS4Free 9.1.0.1.431, as I wrote here:
viewtopic.php?f=16&t=61&start=20#p7628

When I check my ZFS pool status, everything is okay, but I see a message that my pool uses an older version:

Code: Select all

  pool: zfspool
 state: ONLINE
status: The pool is formatted using an older on-disk format.  The pool can
	still be used, but some features are unavailable.
action: Upgrade the pool using 'zpool upgrade'.  Once this is done, the
	pool will no longer be accessible on older software versions.
  scan: none requested
config:

	NAME          STATE     READ WRITE CKSUM
	zfspool       ONLINE       0     0     0
	  raidz1-0    ONLINE       0     0     0
	    ada2.nop  ONLINE       0     0     0
	    ada3.nop  ONLINE       0     0     0
	    ada0.nop  ONLINE       0     0     0
	    ada1.nop  ONLINE       0     0     0

errors: No known data errors

After doing some reading, I've realized that I can upgrade the ZFS pool from v15 to v28.
I've read some posts saying that although v28 has some nice new features, its performance is sometimes worse than v15.

What do you think? Should I upgrade my ZFS pool or not?
My ZFS pool is working fine now and I'm very happy with it... So what benefits does v28 give over v15 when using a standard 4x2TB RAID-Z pool?

[raulfg3]

It's strongly recomended to upgrade, but only if all works fine for you, please wait one week and test your NAS , if all works fine, you can safely upgrade ZFS to v28 by WebGUI.

and remember upgrade ZFS is one way , you can't revert if you need.

[pixies]

Thanks, I'll take your advice and will upgrade, I guess mostly for important bug fixes between the 2 versions.
How long is the process of upgrading the pool (4x2TB, around 50% is full)?
Is it many hours like re-silvering a replaced disk or is it a shorter process?

[raulfg3]

it's inmediately. = 1 or 2 sec.

[pixies]

Great. Thanks for your answers.