[Beowulf] Software RAID?

[stephen mulcahy]

Joe Landman wrote:
> RAID10 is not that hard in software, the hotswap is harder.  Cold-swap 
> *may* be possible (last I looked it should work, haven't tried it 
> recently on SATA).  The issue is whether or not the driver drags the 
> kernel screaming and kicking into a kernel panic when a device is 
> removed ...

Last time I worked on a system with software RAID on Linux was 2 or 3 
years ago. At the time, the server using it experienced a drive failure 
and on reboot - the system got confused about which disk was which and 
tried to mount a different disk from another RAID set.

I'm uncertain of how exactly it was configured on that server and 
whether it was a misconfiguration in the RAID config or a failure in the 
RAID driver that caused the confusion - but it set me back a few years 
in terms of trusting software RAID.

I'm nearly ready to trust it again - I assume it's a little more robust 
these days and handles single drive failures robustly? I suppose the 
suggestion that cold-swap *may* be possible scared me a little there 
again :)

-stephen, hugging his 3ware hw raid card

-- 
Stephen Mulcahy, Applepie Solutions Ltd., Innovation in Business Center,
GMIT, Dublin Rd, Galway, Ireland.  +353.91.751262  http://www.aplpi.com
Registered in Ireland, no. 289353 (5 Woodlands Avenue, Renmore, Galway)