[CentOS] Re: IHC7 RAID-1 or Kernel Software RAID-1?
feizhou at graffiti.net
Fri Jul 20 01:10:33 UTC 2007
>> Oh, if you want to try the hardware raid is faster than software raid
>> line, then I have got news for you. Some time back, there was this i960
>> chip from Intel that was very popular on hardware raid solutions. It
>> sucked. It sucked big time. Yes, it did offload a fair bit of cpu
>> processing from the AMD/Intel cpus then but the i960 was so slow, using
>> software raid was just a no brainer since you get twice the speed for a
>> 10% cpu load.
>> Today, hardware raid come with big memory caches and that is the only
>> reason they are faster than software raid in certain cases like raid5.
>> Any hardware raid card that does not come with a memory cache is not
>> likely to be much faster than a software raid solution especially when
>> using the more complicated raid arrays like raid5/6. You will notice
>> that products from 3ware and Areca all now come with memory caches.
>> There is no such thing as a cheap hardware raid card.
> The i960 doesn't count, since it hasn't been used for a while. I think it was
> designed as a printer rendering engine processor, and was never designed for
> the load that raid imposed.
I did say that the i960 WAS very popular some time back.
But yes, I suppose I was not very explicit on the fact that although
hardware raid cards today come with much more powerful processors, they
still need memory cache to get performance benefits over software raid.
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