Graphing Hard Disk Temperatures with rrdtool (part 2)
Last month I made a post about using rrdtool and ruby to graph hard disk temperatures. I recently had some hardware trouble and something with permissions went crazy. Today I took the time to look into the problem and fix it.
The /dev/hd[egik] device nodes were owned by root:disk and 660. However, the hddtemp binary was trying to do some restricted ioctl operations. Even though the binary was setuid and my non-root user was in the disk group I couldn’t access the disk to get the temperatures.
I found out that there is a hddtemp daemon which can query the disks for my unpriveleged user.
The daemon listens on a TCP port and provides output like this:
|/dev/hde|ST3160811AS|39|C||/dev/hdg|ST3160811AS|40|C||/dev/hdi|ST3160811AS|38|C||/dev/hdk|ST3160815AS|39|C|
Should be easy to modify my disk_temperature.rb to connect to that port and parse the data.
Now my temperature graphs will have new data (as soon as the change is made).
