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Re: Database performance



At 2004-04-04T14:54:08Z, Chris Metzler <cmetzler@speakeasy.net> writes:

> On Sat, 03 Apr 2004 23:42:27 -0600
> Kirk Strauser <kirk@strauser.com> wrote:

>> Not really.  Concurrent mirrored reads can be significantly faster than
>> striped reads, since each drive can be servicing a complete read request
>> simultaneously.

> RAID 0 functions the same way.  Consecutive chunks of data alternate
> between the disks.

Yes, but if two processes are trying to read a blocks that live on the same
disk, then one of them has to wait.  With mirroring, both processes can read
their data simultaneously.  Mirroring is significantly faster than striping
on all *concurrency* benchmarks that I've seen.
-- 
Kirk Strauser
In Googlis non est, ergo non est.

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