On Fri, Nov 6, 2009 at 5:05 PM, Scott Marlowe <scott.marlowe@xxxxxxxxx> wrote: > Have you noticed any fall off in performance as they get re-written a > lot? I'm wondering just how much of the issues with fragmentation > have been fixed versus just putting the problem further into the > future... There has been no drop-off in sequential read speed (around 400MB/s, or 200MB/s per drive) that I have noticed. As for write speed, I haven't benchmarked it with a system that is sufficiently repeatable to detect minor differences, but it still seems as fast as ever. I've overwritten my disk many, many times (not erased - just lots of database inserts and deletes). It should be as completely fragmented as it is ever going to get. Right now I'm getting 110MB/s when I copy a large file from one part of the SSD array to another part (so simultaneous 110MB/s read and 110MB/s write, on an array that is 89% full, and one CPU core at 100% doing something else, and a database doing around 50 reads and 10 writes per second elsewhere on the same disks). It would probably do a little better if I could try it on a fully idle system, but I don't think it would make much of a difference. Halve those numbers for the speed of a single X-25M. Stephen -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
