Re: postgresql 8.3 tps rate

David Rees wrote:
> On Thu, Jan 22, 2009 at 1:27 PM, Ibrahim Harrani
> <ibrahim(dot)harrani(at)gmail(dot)com> 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