Re: Tuning Linux for high-speed disk subsystems

[Martin Knoblauch <Martin.Knoblauch@TeraPort.de>]

> Re: Tuning Linux for high-speed disk subsystems
> 
> 
> > As I count your disks may be the double for the best case. I read here on
> > LKML a post that someone claims that W2k deliever 250 MB/s with such a
> > configuration. Linux 2.4 should do the same. Ask the SCSI gurus.
> >
> 
> That may have been my post you refer to. With 2x5 disks, each capable of
> 50 MB/s by itself, we can stream 255 MB/s very smoothly in either direction
> with W2K --- as long as FILE_FLAG_NOBUFFER is used. With standard
> reads the number is more like 100 MB/s if I recall correctly, so the buffer
> cache can definitely get in the way.
> 
> With Linux + XFS I was getting 250 MB/s read and 220 MB/s write (with a
> bit less smoothness than W2K) using O_DIRECT and no high mem to avoid
> bounce buffer copies. Using standard reads the numbers drop to around
> 120 MB/s. That was a couple of weeks ago and I want to try tweaking some
> more but a co-worker has "borrowed" pieces of the hardware for the moment.
> 
Marvin,

 could you elaborate a bit more :-), or point me/us to your post
(couldn't find it). We are currently evaluating solutions for doing HDTV
playback for one of our customers. This will need about 300-320 MB/sec
read. We know (at least someone claims so) that you can do it with SGI
equipment at a price. The goal for the customer is to definitely beat
that price :-))

Martin
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