slightly OT (FC2): RAID 1 rebuild time

[Taylor, ForrestX]

On Sun, 2004-08-15 at 14:25, Richard Welty wrote:
> this is a little OT, but the system is at least running FC2.
> 
> i have an ibm X330 with a ServeRAID 4Lx controller (secretly a
> mylex controller). i have been running it with a pair of IBM SCSI
> drives (the ones supplied with it), in RAID 1.
> 
> i recently decided i wanted to verify that rebuilding worked properly;
> i took a "IBM" hotswap unit (a Quantum of slightly larger capacity in
> an IBM tray) and swapped it in, first marking the drive it was replacing
> defunct using the IBM utility (the utility is for RH 9, but it seems to work
> ok in FC2). it appeared automagically go to rebuild mode as soon as
> it went in.
> 
> it's two days later, and the drive is still rebuilding. just how long should
> such a rebuild take? anyone know? there are no error messages; the
> ibm RaidMan utility beeps every so often, but the drive is simply labeled
> "rebuilding" in its properties panel.

Check /proc/mdstat to see how far along you are.  When I was setting up
an AS 2.1 machine, I had to increase the minimum speed:

echo 80000 > /proc/sys/dev/raid/speed_limit_min

That made the RAID rebuild go significantly faster.  I think that I
found a bugzilla report about it, but I don't see it now.  If that works
for you, you may want to file a bug report to increase the minimum speed
to something more sane.  I don't think that I actually got 80M/s, but it
was significantly faster than the 1M/s original rate.

Forrest