Date: Wed, 04 Mar 1998 11:14:28 -0800 (PST) From: Simon Shapiro <shimon@simon-shapiro.org> To: Karl Denninger <karl@mcs.net> Cc: grog@lemis.com, hackers@FreeBSD.ORG, blkirk@float.eli.net, jdn@acp.qiv.com, tlambert@primenet.com, sbabkin@dcn.att.com, Wilko Bulte <wilko@yedi.iaf.nl> Subject: Re: SCSI Bus redundancy... Message-ID: <XFMail.980304111428.shimon@simon-shapiro.org> In-Reply-To: <19980304081523.61560@mcs.net>
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On 04-Mar-98 Karl Denninger wrote: ... > Hmmm.... Well, I made some adjustments to the queueing algorythm in the > controller this morning, and guess what - I now get ~17MB/Sec on two SCSI > busses in RAID 0+1 mode. Now *that's* not bad. In RAID 5 mode I'm > getting > ~10MB/sec still, and I think I'm hitting the wall now on the disk I/O > (since > RAID 5 doesn't stripe data) rather than on the interface! These are good numbers. Play with RAID-5 stripe size. You may see jumps in perfromance. > Curiously enough, turning read-ahead in the controller on actually slows > it *down* a bit. Not much, but a little bit. Of course. For RAID-5 it is normal. I set the DPT to ZERO. Simon To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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