Date: Wed, 4 Mar 1998 20:19:51 +0100 (MET) From: Wilko Bulte <wilko@yedi.iaf.nl> To: shimon@simon-shapiro.org Cc: karl@mcs.net, sbabkin@dcn.att.com, tlambert@primenet.com, jdn@acp.qiv.com, blkirk@float.eli.net, hackers@FreeBSD.ORG, grog@lemis.com Subject: Re: SCSI Bus redundancy... Message-ID: <199803041919.UAA01618@yedi.iaf.nl> In-Reply-To: <XFMail.980303212310.shimon@simon-shapiro.org> from Simon Shapiro at "Mar 3, 98 09:23:10 pm"
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As Simon Shapiro wrote... > > On 04-Mar-98 Karl Denninger wrote: > > ... > > I always thought news is an excellent candidate for a heavily cached RAID-0. > 8 stripes or better. Some of my customers insist on RAID-5 which is very > slow on WRITE. Never understood why. I figured out, whith 8 stripes on a > RAID-0, you will fail /var/spool/news aboutevery 18 months. News is volatile data IMHO. If you loose it, though luck. So striping is fine. Or use RAID0+1 if you insist on disk redundancy (and have some money to burn on the project) > >> True. Your perfromance also goes up with the smaller drives. You can > >> stripe better. I think I mentioned it before in this forum; Most DBMS > >> benchmarks only use 300MB of the disk. This is sort of the ``sweet > >> spot'' > >> between system cost and perfrormance. > > > > To a point this is true. The problem is that the smaller disks rotate > > slower, and have bit densities that are lower. > > Yup. This is where you see a benchmark machine using 200 4 GB drives for a > database of 50GB. Nobody can affrd such machine, but benchmarks being what > they are. Interestingly enough these benchmarks are mostly run with direct attached disks, no RAID controller in sight. Assuming enough CPU horsepower (a AlphaServer 8400 will do just fine with 8x 625Mc CPU will do...) you do striping on the machine. Lots faster than any RAIDbox. Who cares about data integrity, it is TPC you want for the glossies. Wilko _ ______________________________________________________________________ | / o / / _ Bulte email: wilko @ yedi.iaf.nl http://www.tcja.nl/~wilko |/|/ / / /( (_) Arnhem, The Netherlands - Do, or do not. There is no 'try' --------------- Support your local daemons: run [Free,Net,Open]BSD Unix -- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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