Hi Craig, Here is the result. It seems that disk write is terrible!. root@myserver /usr]# time (dd if=/dev/zero of=bigfile bs=8192 count=1000000; sync) 1000000+0 records in 1000000+0 records out 8192000000 bytes transferred in 945.343806 secs (8665630 bytes/sec) real 15m46.206s user 0m0.368s sys 0m15.560s [root@myserver /usr]# [root@myserver /usr]# time dd if=bigfile of=/dev/null bs=8192 1000000+0 records in 1000000+0 records out 8192000000 bytes transferred in 174.646798 secs (46906099 bytes/sec) real 2m54.663s user 0m0.246s sys 0m9.307s On Fri, Jan 23, 2009 at 12:44 AM, Craig James <craig_james@xxxxxxxxxxxxxx> wrote: > David Rees wrote: >> >> On Thu, Jan 22, 2009 at 1:27 PM, Ibrahim Harrani >> <ibrahim.harrani@xxxxxxxxx> wrote: >>> >>> Version 1.93d ------Sequential Output------ --Sequential Input- >>> --Random- >>> Concurrency 1 -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- >>> --Seeks-- >>> Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP >>> /sec %CP >>> myserver 300M 391 97 9619 1 8537 2 673 99 +++++ +++ 1196 16 >>> Latency 211ms 388ms 325ms 27652us 722us >>> 6720ms >>> Version 1.93d ------Sequential Create------ --------Random >>> Create-------- >>> myserver -Create-- --Read--- -Delete-- -Create-- --Read--- -Delete-- >>> files /sec %CP /sec %CP /sec %CP /sec %CP /sec %CP /sec >>> %CP >>> 16 9004 25 +++++ +++ +++++ +++ 8246 20 +++++ +++ +++++ >>> +++ >>> Latency 592ms 208us 102us 673ms 179us >>> 100us >> >> You should be testing bonnie with a file size that is at least double >> the amount of memory in your machine - in this case, 4GB files, not >> 300MB files. >> >>> When I compare my bonnie++ result with the one at >>> http://www.westnet.com/~gsmith/content/postgresql/pg-disktesting.htm, >>> It seems that there is something wrong with the disks!? >> >> Yes, your machine appears to be very slow. You should be able to >> write in the order of 30-50MB/s+ and read in the order of 40-80MB/s+. >> Random IO should be in the 200 tps range for a 7200rpm SATA RAID1. > > Have you tried the really basic speed test? > > time (dd if=/dev/zero of=bigfile bs=8192 count=1000000; sync) > > time dd if=bigfile of=/dev/null bs=8192 > > Divide 8.2GB by the times reported. On a single 10K SATA drive, I get about > 55MB/sec write and 61 MB/sec read. > > If you can't get similar numbers, then something is wrong. > > Craig > -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
