On 07/23/2010 11:19 AM, Ted Ts'o wrote:
On Fri, Jul 23, 2010 at 11:13:52AM -0400, Jeff Moyer wrote:
I don't think so. In all of the configurations tested, I'm pretty sure
we saw a performance hit from doing the TRIMs right away. The queue
flush really hurts. Of course, I have no idea what you had in mind for
the amount of time in between batched discards.
Sure, but not all the world is SATA-attached SSD's. I'm thinking in
particular of PCIe-attached SSD's, where the TRIM command might be
very fast indeed... I believe Ric Wheeler tells me you have TMS
RamSan SSD's in house that you are testing? And of course those
aren't the only PCIe-attached flash devices out there....
- Ted
I think that some of the PCI-e cards might want that information right
away, a lot of high end arrays actually prefer fewer larger chunks.
One other user might be virtual devices or some remote replication
mechanism. I wonder if the drbd people for example might (do?) use these?
ric
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