On Tue, 19 Jun 2001, Patrizio Bruno wrote:
> > BTW, why did you change the chunksize? By default it is 256000 and I
> > tested it for speed with many different values. 256000 seemed to be best
> > value. If you have any experience showing that I was wrong, please share
> > it with me.
>
> I was testing different chunksize looking for the best on SGI's XFS,
> I will let you know some better value than 256000, if one exists :)
I got this result when I first put lower vales like 4kB and 8kB and found
that RAID takes too much of CPU time. When using RAID, instead of single
syscalls open/read/write/seek/tell/close mysql calls then many
times. Syscalls are very expensive in time in many operating systems and I
got no slowdown when I increased raid chunk value to be so high as
256000kBytes. I think this is the good value as such amount of data can be
fitted into hard disk hardware cache and can speed up writing do disk many
times. Because this I do not suggest to extend it also. Default value
should be good for most cases.
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