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I track a lot of parameters on my Server and the only thing I can't realy put in perspective is the IOstat. It is a MySQL Server, is this a good result, or should I worry?
root:/var/lib/mysql# iostat -xc
Linux 2.6.28-11-server () 07/25/2009 _x86_64_ (8 CPU)
avg-cpu: %user %nice %system %iowait %steal %idle
3.66 0.19 0.45 1.04 0.00 94.69
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 2.55 871.36 1.46 27.67 392.40 7200.45 260.64 1.02 34.85 2.48 7.22
sda1 0.18 0.61 0.03 0.01 3.60 4.98 215.91 0.01 185.95 19.25 0.08
sda2 0.01 0.00 0.00 0.00 1.03 0.02 919.32 0.00 21.36 6.94 0.00
sda3 2.36 870.75 1.43 27.66 387.76 7195.46 260.68 1.01 34.65 2.48 7.21
sdb 2.37 871.36 1.63 27.67 392.69 7200.45 259.12 0.65 22.07 2.51 7.35
sdb1 0.17 0.61 0.04 0.01 3.59 4.98 187.33 0.01 110.67 12.54 0.06
sdb2 0.00 0.00 0.00 0.00 1.03 0.02 256.48 0.00 2.36 1.50 0.00
sdb3 2.19 870.75 1.60 27.66 388.06 7195.46 259.23 0.64 21.93 2.51 7.34
md0 0.00 0.00 0.38 0.62 3.06 4.96 8.00 0.00 0.00 0.00 0.00
md1 0.00 0.00 0.00 0.00 0.00 0.02 8.36 0.00 0.00 0.00 0.00
md2 0.00 0.00 2.01 898.28 62.49 7186.28 8.05 0.00 0.00 0.00 0.00
Also what war options for decreasing read / write activity?
The write load is quite high on the tables.
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The -m parameter tells iostat to display metrics in megabytes per second instead of blocks or kilobytes per second. The 5 parameter causes iostat to recalculate its metrics every 5 seconds causing the numbers to be an average over this interval.
iostat (input/output statistics) is a computer system monitor tool used to collect and show operating system storage input and output statistics. It is often used to identify performance issues with storage devices, including local disks, or remote disks accessed over network file systems such as NFS.
The iostat command is useful for determining disk and CPU usage. The AIX® operating system maintains a history of disk activity. In the following example, the disk I/O history is disabled because the following message is displayed: Disk history since boot not available.
If anyone worrying about the disk IO bottlenecks, please have a check with the following command. iostat
If this tool is not installed then,
apt-get install sysstat
on Debian based servers.
yum install sysstat
on Redhat/CentOS based servers.
Then,
iostat -x -d sda -here "sda" denotes your HDD
Output:
[email protected]:~# iostat -x -d sda
Linux 2.6.32-24-server (forum.innovationframes.com) 10/01/2011 _x86_64_ (1 CPU)
Dev: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm **%util**
sda 0.01 0.04 0.06 0.03 1.34 0.51 21.77 0.00 5.23 0.30 **0.00**
Note: If Util shows more than 75-80% then you should keep an eye on your HDD.
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