Re: Sharing SCSI disks

David S. Miller (
Thu, 20 Mar 1997 18:53:33 -0500

From: (Alan Cox)
Date: Thu, 20 Mar 1997 21:50:28 +0000 (GMT)

The right solution is simply to add raw devices to the Linux
kernel, it doesn't look too bad or alternatively to add a raw
semantic to the existing ones (which is basically how you'd do

I brought up this with Linus once, the conversation was in reference
to how we thought we could do on database benchmarks etc. which is
essentially all over raw block devices these days. (which we both
agreed was entirely stupid, the kernel should be doing buffer caching,
not some silly Oracle disk I/O layer) In any event, it is just
essentially page flipping every request to dma out to the disk. The
cpu never touches any of this stuff (in the kernel that is).

It is a much easier task than network page flipping thats for sure.

Yow! 11.26 MB/s remote host TCP bandwidth & ////
199 usec remote TCP latency over 100Mb/s ////
ethernet. Beat that! ////
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David S. Miller, /_____________/ / // /_/ ><