[OmniOS-discuss] Status of TRIM support?

[Richard Elling]

On May 28, 2014, at 7:08 AM, Schweiss, Chip <chip at innovates.com> wrote:

> The 840 Pro doesn't have a super cap, but it does properly honor cache flushes which ZFS will do on a log device.   This drastically reduces it's write performance and makes it a poor choice for a log device.

This is a common issue for Flash SSDs, one that shouldn't be underestimated. I've measured
cache flushes in the dozens of ms range on some "value" SSDs. For the enterprise-grade Flash
SSD market, supercaps and better algorithms are usually well worth the expense. For the 
better models, you can disable cache flush in sd.conf allowing you to have fast "barriers" for
those devices that support them without risking data on the devices that do need proper cache
flushing. This is the preferred method over disabling ZFS cache flush altogether.
 -- richard
--

Richard.Elling at RichardElling.com
+1-760-896-4422



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