"Hot spare"?

[danzg]

Is a "hot spare" an extra, attached disk that can automatically take over for a failed disk in the RAID ... ?

If so, how do I set it up properly?

Is it safe to use with FreeNAS 8.2p1? There is a warning in the docs - "Use this option with caution as there is a known bug in the current FreeBSD implementation."

Will the system immediately replace a failed disk without user interaction?

thanks!

 

[danzg]

I found some info ...

I did `zpool add raid-5x3 spare ada0`

Now zpool status shows

Code:

  pool: raid-5x3
 state: ONLINE
 scrub: scrub completed after 11h45m with 0 errors on Sat Aug 18 10:34:21 2012
config:

	NAME        STATE     READ WRITE CKSUM
	raid-5x3    ONLINE       0     0     0
	  raidz1    ONLINE       0     0     0
	    ada1p2  ONLINE       0     0     0
	    ada2p2  ONLINE       0     0     0
	    ada4p2  ONLINE       0     0     0
	    ada5p2  ONLINE       0     0     0
	    ada3p2  ONLINE       0     0     0
	spares
	  ada0      AVAIL   

Is that all? No need to format / create volume / etc .. ?

 

[survive]

Hi danzg,

Nope, there's nothing to do. Unfortunately FreeNAS doesn't actually do hot spares, it can't detect a drive failure & automatically start a rebuild...so what you have now just means you won't have to crack the case to swap out a filed drive for a good one, you will have to crack it after to remove the failed drive and add a new spare. Useful if the system is remote or something. If you haven't gotten to far into life with the system & an redo the pool it might be a better option to recreate it as a raidz2 pool so you have the extra parity built in from the start.

-Will

 

[xic044]

Hello guys this are my doubts about hot spares in FreeNAS:

1 - Why TrueNAS (the storage box) has hot spares if it is run by FreeNAS?
2- A ZFS zpool has a configuration option called autoreplace and that should be used in order to activate hot spare characteristics (see Oracle's ZFS documentation http://docs.oracle.com/cd/E19253-01/819-5461/gcvdi/index.html ). Why that whould not work in FreeNAS? I don't have a spare disk in order to test...