From: Yeb Havinga <yebhavinga@gmail.com>
To: Sebastian Melchior <webmaster@mailz.de>
Cc: Scott Marlowe <scott.marlowe@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Sudden Query slowdown on our Postgresql Server
Date: Fri, 23 Mar 2012 08:10:37 +0100
Message-ID: <4F6C21ED.903@gmail.com> (raw)
In-Reply-To: <08416066-2163-4D4F-AEE9-93FEDECD1CC3@mailz.de>
References: <03615FD7-20B3-49AB-AC5E-484544D03933@mailz.de>
<20120323004749.GG3938@tamriel.snowman.net>
<E8EB1043-A546-4090-80DD-B0EFFB27241F@mailz.de>
<CAOR=d=3t1fqsV2pFrcfERAxpBfkig6DLAmmvq1aVhKfdh=MciQ@mail.gmail.com>
<08416066-2163-4D4F-AEE9-93FEDECD1CC3@mailz.de>
On 2012-03-23 05:53, Sebastian Melchior wrote:
> Hi,
>
> we already used iostat and iotop during times of the slowdown, there is no sudden drop in I/O workload in the times of the slowdown. Also the iowait does not spike and stays as before.
> So i do not think that this is I/O related. As the disks are SSDs there also still is some "head room" left.
I've seen a ssd completely lock up for a dozen seconds or so after
giving it a smartctl command to trim a section of the disk. I'm not sure
if that was the vertex 2 pro disk I was testing or the intel 710, but
enough reason for us to not mount filesystems with -o discard.
regards,
Yeb
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To: pgsql-performance@postgresql.org
Cc: yebhavinga@gmail.com, webmaster@mailz.de, scott.marlowe@gmail.com
Subject: Re: Sudden Query slowdown on our Postgresql Server
In-Reply-To: <4F6C21ED.903@gmail.com>
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