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Re: H800 + md1200 Performance problem

From: Scott Marlowe <scott(dot)marlowe(at)gmail(dot)com>
To: Cesar Martin <cmartinp(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: H800 + md1200 Performance problem
Date: 2012-04-03 15:32:35
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-performance
On Tue, Apr 3, 2012 at 6:20 AM, Cesar Martin <cmartinp(at)gmail(dot)com> wrote:
> Hello there,
> I am having performance problem with new DELL server. Actually I have this
> two servers
> Server A (old - production)
> -----------------
> 2xCPU Six-Core AMD Opteron 2439 SE
> 64GB RAM
> Raid controller Perc6 512MB cache NV
>   - 2 HD 146GB SAS 15Krpm RAID1 (SO Centos 5.4 y pg_xlog) (XFS no barriers)
>   - 6 HD 300GB SAS 15Krpm RAID10 (DB Postgres 8.3.9) (XFS no barriers)
> Server B (new)
> ------------------
> 2xCPU 16 Core AMD Opteron 6282 SE
> 64GB RAM
> Raid controller H700 1GB cache NV
>   - 2HD 74GB SAS 15Krpm RAID1 stripe 16k (SO Centos 6.2)
>   - 4HD 146GB SAS 15Krpm RAID10 stripe 16k XFS (pg_xlog) (ext4 bs 4096, no
> barriers)
> Raid controller H800 1GB cache nv
>   - MD1200 12HD 300GB SAS 15Krpm RAID10 stripe 256k (DB Postgres 8.3.18)
> (ext4 bs 4096, stride 64, stripe-width 384, no barriers)
> Postgres DB is the same in both servers. This DB has 170GB size with some
> tables partitioned by date with a trigger. In both shared_buffers,
> checkpoint_segments... settings are similar because RAM is similar.
> I supposed that, new server had to be faster than old, because have more
> disk in RAID10 and two RAID controllers with more cache memory, but really
> I'm not obtaining the expected results

What does

sysctl -n vm.zone_reclaim_mode

say?  If it says 1, change it to 0:

sysctl -w zone_reclaim_mode=0

It's an automatic setting designed to make large virtual hosting
servers etc run faster but totally screws with pg and file servers
with big numbers of cores and large memory spaces.

In response to


pgsql-performance by date

Next:From: Scott MarloweDate: 2012-04-03 15:34:30
Subject: Re: H800 + md1200 Performance problem
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Subject: Re: TCP Overhead on Local Loopback

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