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Re: MySQL Performance Woody Vs Sarge

> Jochen Schulz wrote:
> >
> >Again, I think you are searching in the wrong direction. Your 'hdparm
> >-tT' results clearly showed that the great difference between your
> >servers doesn't lie in hard disk performance (48 to 43 MB/s), but in
> >Memory/CPU performance (278 to 58 MB/s).
> That would be a very gross misconfiguration.

Yes, obviously! ;-) I didn't make these numbers up, they are from the
OP's hdparm runs.

>  To me it seems far more
> likely that raid caching is simply disabled, possibly in the driver.

I must give in I don't know anything about raids, but I can read the
hdparm manpage. As I quoted in another message, the numbers above
clearly show that the combination of memory and CPU on the one system is
220 MB/s faster than the other one (because that is what -T does).

And again: even if the hard disk was badly misconfigured - if you do the
same query (read-only) several times, the Linux kernel should cache your
reads so that the hard disk isn't even accessed. Provided that the
system has enough memory, of course.

My clothes aren't just fashion. They're a lifestyle.
[Agree]   [Disagree]

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