Developers guide

Chapter 9

Performance optimization 73

Performance optimization

MySQL optimizations

Tuning MySQL itself

If you’re PacketFence system is acting very slow, this could be due to your MySQL configuration. You

should do the following to tune performance:

Check the system load

# uptime

11:36:37 up 235 days, 1:21, 1 user, load average: 1.25, 1.05, 0.79

Check iostat and CPU

# iostat 5

avg-cpu: %user %nice %sys %iowait %idle

0.60 0.00 3.20 20.20 76.00

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn

cciss/c0d0 32.40 0.00 1560.00 0 7800

avg-cpu: %user %nice %sys %iowait %idle

0.60 0.00 2.20 9.20 88.00

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn

cciss/c0d0 7.80 0.00 73.60 0 368

avg-cpu: %user %nice %sys %iowait %idle

0.60 0.00 1.80 23.80 73.80

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn

cciss/c0d0 31.40 0.00 1427.20 0 7136

avg-cpu: %user %nice %sys %iowait %idle

0.60 0.00 2.40 18.16 78.84

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn

cciss/c0d0 27.94 0.00 1173.65 0 5880

As you can see, the load is 1.25 and IOWait is peaking at 20% - this is not good. If your IO wait is low but

your MySQL is taking +%50 CPU this is also not good. Check your MySQL install for the following variables: