[Beowulf] Software RAID?

stephen mulcahy smulcahy at aplpi.com
Thu Nov 22 06:57:46 PST 2007

Jakob Oestergaard wrote:
> One thing that HW RAID has, though, that SW RAID fundamentally cannot get, is a
> battery backed write cache. This can, for many workloads, prove to give a very
> significant performance advantage (for sync heavy workloads you can get several
> orders of magnitude speedup).  For other workloads it won't matter, of course.

I'd note that battery backed caches on the RAID cards I've looked at in 
the last few months seem to come at a *significant* premium over the 
base price of the card (50-100% type significant).

Not a reason not to opt for it, but the cost-benefit of a battery-backed 
cache versus a UPS backed server might be worth investigating.


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)

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