From: Rémy Beaumont <remyb@medrium.com>
To: josh@agliodbs.com
Cc: pgsql-performance@postgresql.org
Subject: Re: High load and iowait but no disk access
Date: Tue, 30 Aug 2005 14:42:38 -0400
Message-ID: <22924e579ad7e7e0deb5133eb905618b@medrium.com> (raw)
In-Reply-To: <200508301132.06904.josh@agliodbs.com>
References: <bcd92b00545ffeef542f68666144099d@medrium.com>
<200508301132.06904.josh@agliodbs.com>
On 30-Aug-05, at 14:32, Josh Berkus wrote:
> Remy,
>
>> The behavior we see is that when running queries that do random reads
>> on disk, IOWAIT goes over 80% and actual disk IO falls to a crawl at a
>> throughput bellow 3000kB/s (We usually average 40000 kB/s to 80000
>> kB/s
>> on sequential read operations on the netapps)
>
> This seems pretty low for a NetApp -- you should be able to manage up
> to
> 180mb/s, if not higher. Are you sure it's configured correctly?
Hi Josh,
The config has been reviewed by NetApp. We do get rates higher then
80mb/s, but on average, that's what we get.
Do you have NetApp filers deployed ?
How many spindles do you have in your volume ?
On which OS are you running Postgres ?
Thanks,
Rémy
>
> --
> --Josh
>
> Josh Berkus
> Aglio Database Solutions
> San Francisco
>
> ---------------------------(end of
> broadcast)---------------------------
> TIP 9: In versions below 8.0, the planner will ignore your desire to
> choose an index scan if your joining column's datatypes do not
> match
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: remyb@medrium.com, josh@agliodbs.com
Subject: Re: High load and iowait but no disk access
In-Reply-To: <22924e579ad7e7e0deb5133eb905618b@medrium.com>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox