On 12/22/2010 7:05 AM, Christopher George wrote:
I'm not sure if TRIM will work with ZFS.
Neither ZFS nor the ZIL code in particular support TRIM.
I was concerned that with trim support the SSD life and
write throughput will get affected.
Your concerns about sustainable write performance (IOPS)
for a Flash based SSD are valid, the resulting degradation
will vary depending on the controller used.
Best regards,
Christopher George
Founder/CTO
www.ddrdrive.com
Christopher is correct, in that SSDs will suffer from (non-trivial)
performance degredation after they've exhausted their free list, and
haven't been told to reclaim emptied space. True battery-backed DRAM is
the only permanent solution currently available which never runs into
this problem. Even TRIM-supported SSDs eventually need reconditioning.
However, this *can* be overcome by frequently re-formatting the SSD (not
the Solaris format, a low-level format using a vendor-supplied
utility). It's generally a simple thing, but requires pulling the SSD
from the server, connecting it to either a Linux or Windows box, running
the reformatter, then replacing the SSD. Which, is a PITA.
But, still a bit cheaper than buying a DDRdrive. <wink>
--
Erik Trimble
Java System Support
Mailstop: usca22-123
Phone: x17195
Santa Clara, CA
Timezone: US/Pacific (GMT-0800)
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