Re: md faster than h/w?

[Max Waterman <davidmaxwaterman+gmane@fastmail.co.uk>]

Andargor wrote:
> 
> --- Max Waterman
> <davidmaxwaterman+gmane@fastmail.co.uk> wrote:
> 
>>Of course, bonnie++ only works on mounted devices,
>>but gives me
>>reasonable (but not great) numbers (130MB/s) which
>>don't seem to vary
>>too much with the kernel version.
> 
> 
> Out of curiosity, have you compared bonnie++ results
> with and without -f (fast)?

Nope. Just used default options (as well as the '-u' and
'-d' options, of course).

> 
> I've found that it seems to report x2 read throughput
> without -f. Perhaps it "warms up" the drive with
> putc() and getc(), allowing the kernel and/or cache to
> do its job?

Hrm.

> 
> I haven't found a benchmark that is 100%
> reliable/comparable. Of course, it all depends how the
> drive is used in production, which may have little
> correlation with the benchmarks...

Indeed.

Do you think that if it is configured for the best possible
read performance, then that would be it's worst possible
write performance?

I was hoping that having it configured for good read perf.
would mean it was pretty good for write too....

Max.

> 
> Andargor
> 
> 
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