Pathetic SATA performance
I have a file server, running Etch, with the following specs:
2 x SI based SATA I controllers
4 x Maxtor 250GB SATA drives
It is set up with software RAID 5, and the overall performance is terrible.
Every time it reboots (which happens due to dodgy power!), it does a RAID
resync, this takes up 90% CPU time (for md0_resync process) for 50 hours!!
During this time, ANY access to the drive is painful.
Now, I expected software RAID 5 to be slow, but not this bad - this is the
reading from hdparm:
bungo:~# hdparm -tT /dev/md0
Timing cached reads: 2 MB in 4.71 seconds = 435.05 kB/sec
Timing buffered disk reads: 8 MB in 3.13 seconds = 2.56 MB/sec
Becuase they're SATA drives, hdparm cannot tune them - or indeed read their
current settings. Is there any way I can speed this beast up, if not I am
going to go back to my old PPro200-based file server, running SCSI->FCAL