Hi there, Linux kernel 2.6.20 and later supports per process I/O accounting. You can access every process/thread's I/O read/write values by using /proc filesystem. You can check if your kernel has built with I/O account by just simply checking /proc/self/io file. If it exists then you have I/O accounting built-in.
I use that to have real I/O stats for lmtp, imap and pop in Cyrus. You just need ioconf = yes in your conf to activate I/O stats. The code autodetect if your kernel support I/O account and disable the stats if not. You can find the git branch with the code here : https://github.com/worldline-messaging/cyrus-imapd/tree/io-stat Olivier ROLAND AtoS