Den 30/11/2012 kl. 02.24 skrev "Kevin Grittner" <kgrittn@mail.com>:
> Niels Kristian Schjødt wrote:
>
>> Okay, now I'm done the updating as described above. I did the
>> postgres.conf changes. I did the kernel changes, i added two
>> SSD's in a software RAID1 where the pg_xlog is now located -
>> unfortunately the the picture is still the same :-(
>
> You said before that you were seeing high disk wait numbers. Now it
> is zero accourding to your disk utilization graph. That sounds like
> a change to me.
>
>> When the database is under "heavy" load, there is almost no
>> improvement to see in the performance compared to before the
>> changes.
>
> In client-visible response time and throughput, I assume, not
> resource usage numbers?
>
>> A lot of both read and writes takes more than a 1000 times as
>> long as they usually do, under "lighter" overall load.
>
> As an odd coincidence, you showed your max_connections setting to
> be 1000.
>
> http://wiki.postgresql.org/wiki/Number_Of_Database_Connections
>
> -Kevin
Hehe, I'm sorry if it somehow was misleading, I just wrote "a lot of I/O" it was CPU I/O, it also states that in the
chartin the link.
However, as I'm not very familiar with these deep down database and server things, I had no idea wether a disk bottle
neckcould hide in this I/O, so i went along with Shauns great help, that unfortunately didn't solve my issues.
Back to the issue: Could it be that it is the fact that I'm using ubuntus built in software raid to raid my disks, and
thatit is not at all capable of handling the throughput?