Recently found that PHP run automatically load class functions always time out, tracking the PHP slow query log, found that the application card in the Include a class file when the time out.
Initial positioning is the IO response timeout, hard disk read problem.
To navigate by several commands:
iostat-d-x-k 1 10//Run 10 times View the wait parameter in Iostat is very large, generally not more than 5ms,await SVCTM the closer the 2 parameters, the better the IO performance.
Refer to other blogs,
Await: The average time (in milliseconds) of processing per IO request. This can be understood as the response time of IO, generally the system IO response time should be less than 5ms, if greater than 10ms is relatively large. this time includes the queue time and service time, that is, in general, await is greater than SVCTM, their difference is smaller, then the shorter the queue time, conversely, the greater the difference, the longer the queue time, indicating that the system has a problem. SVCTM represents the average service time (in milliseconds) for each device I/O operation. If the value of SVCTM is close to await, indicating that there is little I/O waiting, disk performance is good, and if the value of await is much higher than the value of SVCTM, the I/O queue waits too long for the applications running on the system to become slower.
sudo iotop-o,//View the program on the drive, view process IO occupancy ratio
sudo perf Top//view process IO occupancy ratio
sudo hdparm-t/dev/**** view disk read efficiency
Display: Timing buffered disk reads:10 MB in 3.14 seconds = 3.18 Mb/sec
View non-disruptive sleep
While true; do date; PS AUXF | awk ' {if ($8== "D") print $;} '; Sleep 1; Done
After tracking through the above command, hard disk reading efficiency is very low, further reasons, it is not known, speculation may be the hard drive has bad channel.
Ps:
http://my.oschina.net/leejun2005/blog?disp=2&catalog=186193