ionice: renice for your I/O operations
A few months ago I posted a crazy solution that would allow me to write a large file to disc without killing disk I/O and causing other production services to be impacted. I post this as a follow up to that. Shortly after making that post I learned of a utility called ionice, which takes advantage of Linux’s I/O scheduling capabilities. This utility is something akin to renice, but for disc I/O scheduling instead of CPU scheduling. I use it all the time now and the servers I manage are more stable because of it.
On the same note, I’d like to give a plug for another really nice tool called iotop. It’s a python program which gives an interface similar to top. It displays useful information about which processes are using disc I/O and how much.