On Wed, 26 Dec 2007, Mark Mielke wrote:
> Florian Weimer wrote:
>>> seek/read/calculate/seek/write since the drive moves on after the
>>> read), when you read you must read _all_ drives in the set to check
>>> the data integrity.
>>>
>> I don't know of any RAID implementation that performs consistency
>> checking on each read operation. 8-(
>>
>
> Dave had too much egg nog... :-)
>
> Yep - checking consistency on read would eliminate the performance benefits
> of RAID under any redundant configuration.
except for raid0, raid is primarily a reliability benifit, any performance
benifit is incidental, not the primary purpose.
that said, I have heard of raid1 setups where it only reads off of one of
the drives, but I have not heard of higher raid levels doing so.
David Lang