my webserver running centos 5.7 is showing quite a lot of disk write activity which I cannot explain really.
I run a few websites on this server with the help of nginx and php-fpm and xcache. On the file-system i have added noatime.
Now this is running fine, but I'm seeing a high number of writes per second that I cannot explain. There aren't any files being added, I have disabled the nginx access log. The php-fpm error log and nginx error log are only getting a few lines added to it per minute. I've checked all other logs in /var/log and nothign accounts for the number of writes that are happening.
On average there are about 2 megabytes of data per minute being written, at about 200 IO's per second.
How could I find out what is causing these writes?
You are you presently measuring the 200 IOPS? The
iotoputility is a quick way to capture per-process disk I/O stats. You should be able to grab it from the EPEL repository.Another thing that I did is do lsof partition in question. That will sometimes, not always, show you all the files being opened and hence "worked on"
Doesn't always work though.
If sdd is mounted on home4 just do
lsof /home4
and see for yourself.