jandrese at mitre.org
Mon Mar 31 06:36:06 PST 2003
Mattias Pantzare wrote:
> Lukas Ertl wrote:
>> Ok. But I still don't understand why RAID 5 write performance is _so_
>> The CPU is not the bottle neck, it's rather bored. And I don't understand
>> why RAID 0 doesn't give a big boost at all. Is the ahc driver known to be
> To do a RAID 5 write you do this:
> 1. Read the old data on the blocks that you will write to.
> 2. Read the coresponding parity data.
> 3. Write the new data.
> 4. Write the new parity.
Hmm, how about the case where you're writing new data? You shouldn't
have to do steps 1 & 2, and yet the RAID5 write performance is still
I get 4565 K/sec on modern ATA/133 HDDs.
Reading is much better at 91908 K/sec at least.
\ |_ _|__ __|_ \ __| Jason Andresen jandrese at mitre.org
|\/ | | | / _| Network and Distributed Systems Engineer
_| _|___| _| _|_\___| Office: 703-883-7755
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