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Innodb unexplained IOs
Posted by: Bob Bankay ()
Date: January 24, 2005 12:39PM

Running 4.0.13 on Sparc Sol 9. mysql_max.

We have a large table (10 -20GB) that has a lot of volatility. Occasionally in the past we have done reorgs by the usual methods and at one time increased the free space of the innodb files from 20GB to 50GB. So the table was very sparse.

Now we are see a lot of unexplained IOs (in iostat vs mytop) that do not correspond to any queries. Here is a mytop line that show physical IOs:

62.27 reads/s, 17532 avg bytes/read, 21.45 writes/s, 1.73 fsyncs/s

Here is a comparable iostat output for the raid10 volume:

Vol rd/s wr/s Rkb/s Wkb/s IOms Busy%
md40 162.3 19.8 10958.4 482.0 0.0 10.9 60.0 3 100

What is doing the extra 100 reads/sec? When mysql is freshly restarted the large number of reads/sec start without any queries being active. We are concerned because the volume is at 100% busy, we normally see it at 60% busy in iostat.

Any thoughts?


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Subject Views Written By Posted
Innodb unexplained IOs 3263 Bob Bankay 01/24/2005 12:39PM
Re: Innodb unexplained IOs 1761 Bob Bankay 01/24/2005 12:43PM
Re: Innodb unexplained IOs 2186 Heikki Tuuri 01/24/2005 01:09PM
Re: Innodb unexplained IOs 2132 Bob Bankay 01/24/2005 05:40PM
Re: Innodb unexplained IOs 2254 James Day 01/27/2005 05:07AM
Re: Innodb unexplained IOs 2120 Bob Bankay 02/08/2005 04:31PM
Re: Innodb unexplained IOs -still need help! 1913 Bob Bankay 01/26/2005 02:37PM
Re: Innodb unexplained IOs - have finally stopped 2100 Bob Bankay 01/27/2005 06:56PM
Re: Innodb unexplained IOs 1822 Heikki Tuuri 01/31/2005 11:32AM
Re: Innodb unexplained IOs 1906 Bob Bankay 01/31/2005 04:57PM
Re: Innodb unexplained IOs 2108 Jeff Cobb 02/03/2005 06:23PM
Re: Innodb unexplained IOs 2595 James Day 02/03/2005 08:56PM
Re: Innodb unexplained IOs 2145 Jeff Cobb 02/04/2005 01:25PM
Re: Innodb unexplained IOs 2121 James Day 02/04/2005 01:44PM

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