[OmniOS-discuss] Status of TRIM support?

[Jim Klimov]

28 мая 2014 г. 15:51:36 CEST, Dan Swartzendruber <dswartz at druber.com> пишет:
>(merging comments to Saso and Jim)
>
>I don't think I mentioned my environment - if not, my apologies.  This
>is
>a SOHO/Lab setup, so things like zeusram are non-starters.  The basic
>network infrastructure is gigabit, so iSCSI ZIL would suck badly, I
>suspect.  As far as over-provisioning the 840PRO, I have it sliced for
>16GB.  Once it's been running for awhile, I will re-run the disk
>benchmark.  I understand the 840PRO doesn't have a supercap - this was
>basically just a performance analysis to see how it stacks up compared
>to
>sync=disabled and on-pool ZIL.  If I go this route, I will need to look
>for a decent/affordable unit with supercap.  One other test I can try
>is
>with a 15K 76GB SAS 2.5-inch drive I salvaged from a dead server.  It
>should have about 1/2 the latency of a 7200rpm sata drive, and if so
>would
>get me up to about 40MB/sec, which is still not good, but better than
>on-pool ZIL.  I'll find out later.  I have googled a fair amount and
>there
>seems to be 'work in progress' for TRIM support for ZoL and illumos,
>but
>no real indication I could find as to when either might support it.
>
>
>
>_______________________________________________
>OmniOS-discuss mailing list
>OmniOS-discuss at lists.omniti.com
>http://lists.omniti.com/mailman/listinfo/omnios-discuss

Actually, i think that if you have the hdd dedicated for zil, then you only write sequentially to it, so the head hovers where it should be. Track-to-track seek time can be discarded and the worst latency is a single rotation. With much enough data (liky sync=always) you have a 15krpm streaming write... some 200MBps?

//Jim
--
Typos courtesy of K-9 Mail on my Samsung Android