[CentOS] Harware vs Kernel RAID (was Re: External SATA enclosures: SiI3124 and CentOS 5?)
Gordon Messmer
yinyang at eburg.com
Tue Jun 2 16:59:05 UTC 2009
On 06/01/2009 07:52 PM, Michael A. Peters wrote:
>
> I've read a lot of different reports that suggest at this point in time,
> kernel software raid is in most cases better than controller raid.
There are certainly a lot of people who feel that way. It depends on
what your priorities are. Hardware RAID has the advantage of offloading
some calculations from the CPU, and has a write cache which can decrease
memory use. However, both of those are relatively expensive, and
there's no clear evidence that your money is better put into the RAID
card than into faster CPU and more memory. Another important
consideration is that hardware RAID will (must!) have a battery backup
so that any scheduled writes can be completed later in the case of power
loss. If you decide to use software RAID, I would strongly advise you
to use a UPS, and to make sure your system monitors it and shuts down in
the event of power loss.
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