On Tue, Mar 21, 2000 at 01:14:45PM -0800, Rodney W. Grimes wrote:
> > On Tue, Mar 21, 2000 at 09:29:56AM -0800, Matthew Dillon wrote:
> > > :>
> > > :> I would think that track-caches and intelligent drives would gain
> > > :> much if not more of what clustering was designed to do gain.
> > > :
> > > :Hm. But I'd think that even with modern drives a smaller number of bigger
> > > :I/Os is preferable over lots of very small I/Os. Or have I missed the point?
> >
> > > As long as you do not blow away the drive's cache with your big I/O's,
> > > and as long as you actually use all the returned data, it's definitely
> > > more efficient to issue larger I/O's.
> >
> > Prefetching data that is never used is obviously a waste. 256K might be a
> > bit big, I was thinking of something like 64-128Kb
> >
> > Drive caches tend to be 0.5-1Mbyte (on SCSI disks) for modern drives.
>
> Your a bit behind the times with that set of numbers for modern SCSI
> drives. It is now 1 to 16 Mbyte of cache, with 2 and 4Mbyte being the
> most common.
Your drives are more modern than mine ;-) What drive has 16 Mb? Curious
here..
--
Wilko Bulte Arnhem, The Netherlands
http://www.tcja.nl The FreeBSD Project: http://www.freebsd.org
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