On Tue, May 15, 2012 at 8:21 AM, Віталій Тимчишин <tiv...@gmail.com> wrote: > We are using Areca controller with BBU. So as for me, question is: Can 520 > series be set up to handle fsyncs correctly?
No. The cause for capacitors on SSD logic boards is that fsyncs aren't flushed to NAND media, and hence persisted, immediately. SSDs are divided into "pages", called "erase blocks" (usually much larger than the filesystem-level block size; I don't know offhand what the block size is on the 710, but on the older X-25 drives, it was 128K). All writes are accumulated in the on-board cache into erase block sized chunks, and *then* flushed to the NAND media. In a power-loss situation, the contents of that cache won't be preserved unless you have a capacitor. In some drives, you can disable the on-board cache, but that does absolutely atrocious things both to your drive's performance, and its longevity. As the other posters in this thread have said, your best bet is probably the Intel 710 series drives, though I'd still expect some 320-series drives in a RAID configuration to still be pretty stupendously fast. rls -- :wq -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
