From: Christiaan Willemsen <cwillemsen@technocon.com>
To: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: SSD endurance calculations
Date: Mon, 21 Nov 2011 22:03:46 +0100
Message-ID: <zarafa.4ecabcb2.0527.762392872b021f28@meel.technocon.local> (raw)
Hey there,
We are looking at beefing up our servers with SSD's. Some of you did some interesting tests with the Intel 320. So the idea came to make a RAID10 with four 600GB models.
I did however do some calculations with the current database server (220GB database, expected to grow to 1TB by the end of next year). I specifically looked at /proc/diskstat at the read/write figures. From there I could see a read/write ratio of 3:1, and I also saw a wopping 170GB of writes per day (for a database that currently grows 1GB per dag). That seems like an insanely high figure to me! How come? We do mostly inserts, hardly any updates, virtually no deletes.
Secondly, I also looked at the reliability figures of the Intel 320. They show 5 years of 20GB per day, meaning that it will hold up for about 200 days in our system. RAID 10 wil make 400 days of that, but this seems hardly a lot.. Am I missing something here?
Kind regards,
Christiaan
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To: pgsql-performance@postgresql.org
Cc: cwillemsen@technocon.com
Subject: Re: SSD endurance calculations
In-Reply-To: <zarafa.4ecabcb2.0527.762392872b021f28@meel.technocon.local>
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