Date: Wed, 4 Mar 1998 13:14:41 -0600 From: Karl Denninger <karl@mcs.net> To: shimon@simon-shapiro.org 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: <19980304131441.31888@mcs.net> In-Reply-To: <XFMail.980304111428.shimon@simon-shapiro.org>; from Simon Shapiro on Wed, Mar 04, 1998 at 11:14:28AM -0800 References: <19980304081523.61560@mcs.net> <XFMail.980304111428.shimon@simon-shapiro.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Wed, Mar 04, 1998 at 11:14:28AM -0800, Simon Shapiro wrote: > > 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 Do you have a computation available for the 'optimum' stripe size (in blocks)? -- -- Karl Denninger (karl@MCS.Net)| MCSNet - Serving Chicagoland and Wisconsin http://www.mcs.net/ | T1's from $600 monthly to FULL DS-3 Service | NEW! K56Flex support on ALL modems Voice: [+1 312 803-MCS1 x219]| EXCLUSIVE NEW FEATURE ON ALL PERSONAL ACCOUNTS Fax: [+1 312 803-4929] | *SPAMBLOCK* Technology now included at no cost To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?19980304131441.31888>