[TriLUG] raid cards

[Kevin Otte]

Jason Tower wrote:
> but can you hot swap a failed sata disk using software raid?

Sort of.  Linux currently does not support hot-plugging of SATA devices.
 You can "cold-plug" them, which is to say you have to tell the OS
you're about to pull the device so it can safe it first.

> and how will you know which disk has failed?

mdadm provides a monitoring tool that will e-mail alert when a disk fails.

> hardware raid cards will usually tell you (via blinky lights) which
> disk is bad

ahh yes, das blinkenlights are handy.

> so you can replace it on the fly.  that's the thing about hardware
> raid - it's completely abstracted from the OS so you can do these
> things without the system knowing about it.  software raid is
> terrific in many circumstances but it does have limitations.

With the exception of the SATA hotplug issue, most of what has been
discussed are differences in methodology rather than limitations.
Software RAID with SCSI on Linux is a tough act to beat IMHO.

-- Kevin