The replacement drive for my 1TB RAID5 finally came in last night. I had never actually had to do a rebuild with the md toolset before (I’ve always had hardware support in the past). I wasn’t able to find any rebuild option in OpenFiler’s web interface, so I ssh’ed in.
First, I looked at the partition structure of one of the remaining working drives with fdisk -l /dev/sdd, then I matched this partition setup on the replacement drive. Then I added the new drive back into the array with mdadm /dev/md1 -a /dev/sde1, and monitored the rebuild process occasionally by looking at /proc/mdstat.
The total time for the array rebuild was just shy of 4 hours and 30 minutes, on an Atom N270.
If you’ve been to my place, you know my basement sounds like a hair dryer. I have 5 machines running 24/7 most of the time. Noise and electric bills finally got to me, so I picked up a Kill-A-Watt to track power usage, per machine. What I found out is that having those machines on constantly accounts for 1/3 of my electric bill, almost 330 kilowatt-hours per month.
The 2 biggest hits towards power usage were # of drives, and processor type. More drives = more motors to spin. The most power-hungry drives were the Ultra320 SCSI drives, followed by PATA drives and finally SATAs. Processor power usage seemed to follow a slightly different curve, with a 2nd gen P4 using the most power, followed by P3s, Pentium Ds, and the Core 2 Duo.