On Sat, 24 Dec 2005, Luke Lonergan wrote:
Recently, I helped a company named DeepData to improve their dbms
performance, which was a combination of moving them to software RAID50
on Linux and getting them onto Bizgres. The disk subsystem sped up on
the same hardware (minus the HW RAID card) by over a factor of 10. The
downside is that SW RAID is a pain in the neck for management - you have
to shut down the Linux host when a disk fails to replace it.
Luke, you should not need to shut down the linux host when a disk fails.
you should be able to use mdadm to mark the drive as failed, then remove
it from the system and replace it, then use mdadm to add the drive to the
array.
I'm fighting through a double disk failure on my system at home and when I
hit a bad spot on a drive (failing it from the array) I can just re-add it
without having to restart everything (if it's the second drive I will have
to stop and restart the array, but that's becouse the entire array has
failed at that point)
now hot-swap may not be supported on all interface types, that may be what
you have run into, but with SCSI or SATA you should be able to hot-swap
with the right controller.
David Lang
