drives (Not SCSI). This involves things like the block prefetch, the DMA/PIO modes,
and a number of other things.
I'm writing this mini-how-to to help people get more from their system. People often
complain that Linux is a bit slow for them (which it can be) I haven't seen such
a post recently, but I know on TechIMO at least we always used to be talking
people through using hdparm.
As ever, you do all this at your own risk - nothing should go wrong, but it's your fault and not mine if it does.
hdparm can be used on a running system. It doesn't require filesystems on the disk to be unmounted in order to work, so you can play with it all you want. Some settings like -Y will require a hard reboot to get the disk back - use with caution.
All settings will be lost at reboot, so you can play around and find a config that suits you. Also, it can be useful to benchmark the drives using "hdparm -tT" which performs a buffer read and a disk read. For best results do it on a system with no other active processes (to remove external influence)."