TRIM support through ciss

[Dmitry Morozovsky]

On Wed, 5 Jun 2013, Steven Hartland wrote:

> For ZFS you really don't want to use a HW RAID, its much better
> to just give ZFS the raw disks as you gain nice features like
> self healing :)

I know this well, and use it for a dozen servers with regular SATA 
("enterprrize-grade" though, like WD RE4s) extensively; however, ciss does not 
provide an easy way to expose disks -- only via RAID0 per disk

> I've never used ciss, but if you can configure the disks as
> JBOD it may mean it can then support a delete method.
> 
> In addition for TRIM to work all data disks in a pool need to
> support a delete method. L2ARC disks are treated seperately.

well, to be a bit more precise: SSDs are split to have mirrored ZIL and 
splitted L2ARC, and SASes are mirrored in pairs:

root at briareus:/usr/src# zpool status
  pool: br
 state: ONLINE
  scan: scrub repaired 0 in 0h0m with 0 errors on Fri Apr 26 15:29:32 2013
config:

        NAME             STATE     READ WRITE CKSUM
        br               ONLINE       0     0     0
          mirror-0       ONLINE       0     0     0
            gpt/br0      ONLINE       0     0     0
            gpt/br4      ONLINE       0     0     0
          mirror-1       ONLINE       0     0     0
            gpt/br1      ONLINE       0     0     0
            gpt/br5      ONLINE       0     0     0
          mirror-2       ONLINE       0     0     0
            gpt/br6      ONLINE       0     0     0
            gpt/br2      ONLINE       0     0     0
          mirror-3       ONLINE       0     0     0
            gpt/br3      ONLINE       0     0     0
            gpt/br7      ONLINE       0     0     0
        logs
          mirror-4       ONLINE       0     0     0
            gpt/br-zil0  ONLINE       0     0     0
            gpt/br-zil1  ONLINE       0     0     0
        cache
          gpt/br-cache0  ONLINE       0     0     0
          gpt/br-cache1  ONLINE       0     0     0

errors: No known data errors

All I need is TRIM support for ZIL and L2ARC...

-- 
Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
[ FreeBSD committer:                                 marck at FreeBSD.org ]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru ***
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