Bruce Momjian wrote: > Agreed, thought I thought the problem was that SSDs lie about their > cache flush like SATA drives do, or is there something I am missing?
There's exactly one case I can find[1] where this century's IDE drives lied more than any other drive with a cache: Under 120GB Maxtor drives from late 2003 to early 2004. and it's apparently been worked around for years. Those drives claimed to support the "FLUSH_CACHE_EXT" feature (IDE command 0xEA), but did not support sending 48-bit commands which was needed to send the cache flushing command. And for that case a workaround for Linux was quickly identified by checking for *both* the support for 48-bit commands and support for the flush cache extension[2]. Beyond those 2004 drive + 2003 kernel systems, I think most the rest of such reports have been various misfeatures in some of Linux's filesystems (like EXT3 that only wants to send drives cache-flushing commands when inode change[3]) and linux software raid misfeatures.... ...and ISTM those would affect SSDs the same way they'd affect SATA drives. [1] http://lkml.org/lkml/2004/5/12/132 [2] http://lkml.org/lkml/2004/5/12/200 [3] http://www.mail-archive.com/linux-ker...@vger.kernel.org/msg272253.html -- Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
