[OmniOS-discuss] r151014 users - beware of illumos 6214 and L2ARC

[Paul Jochum]

Hi All:

     I had a lot of servers (each with more than 1 zpool on them), so I 
wrote a quick and dirty little script to find all of the cache drives 
and remove them.  It doesn't have any type of error checking in it, but 
unless you remove the three hash marks on the line "### zpool remove $i 
$j), it won't do anything either (other than save a copy of your current 
zpool status under /root/zpool_status-15-09-11.with_cache)s.  Hope this 
help some of you:



export DATE=`date '+%y-%m-%d'`

# Start by getting a current copy of the status
zpool status > /root/zpool_status-$DATE.with_cache

# find all of the pools on the server
for i in `zpool list -H -o name`
do
         # now, get all of the cache drives from that pool
         # (the sed script grabs the lines from "cache" to "spares"
         # the greps remove the "cache" and "spares" line
         # and the awk print the first item from each line, which is
         # the name of the drive
         for j in `zpool status $i | sed -n '/cache/,/spares/p' | \
                 grep -v cache | grep -v spares | \
                 awk '{print $1}'`
         do
                 echo "zpool remove $i $j"
               # uncomment the next line, when you are ready to really 
run this
                ### zpool remove $i $j
         done
done



regards,
Paul


On 09/10/2015 06:53 AM, Dan McDonald wrote:
> If you are using a zpool with r151014 and you have an L2ARC ("cache") vdev, I recommend at this time disabling it.  You may disable it by uttering:
>
> 	zpool remove <pool-name> <cache-vdev-name>
>
> For example:
>
> 	zpool remove data c2t2d0
>
> The bug in question has a good analysis here:
>
> 	https://www.illumos.org/issues/6214
>
> This bug can lead to problems ranging from false-positives on zpool scrub all the way up to actual pool corruption.
>
> We will be updating the package repo AND the install media once 6214 is upstreamed to illumos-gate, and pulled back into the r151014 branch of illumos-omnios.  The fix is undergoing some tests from ZFS experts right now to verify its correctness.
>
> So please disable your L2ARC/cache devices for maximum data safety.  You can add them back after we update r151014 by uttering:
>
> 	zpool add <pool-name> cache <cache-vdev-name>
>
> PLEASE NOTE the "cache" indicator when you add back.  If you omit this, the vdev is ADDED to your pool, an operation one can't reverse.
>
> 	zpool add data cache c2t2d0
>
> Thanks,
> Dan
>
> _______________________________________________
> OmniOS-discuss mailing list
> OmniOS-discuss at lists.omniti.com
> http://lists.omniti.com/mailman/listinfo/omnios-discuss