Date: Fri, 20 Feb 2004 14:35:25 -0500 From: Gary Stanley <gary@outloud.org> To: Charles Swiger <cswiger@mac.com> Cc: freebsd-performance@freebsd.org Subject: Re: strange performance dip shown by iozone Message-ID: <6.0.1.1.2.20040220143227.01ee0ec0@208.141.46.3> In-Reply-To: <D4B74A4C-63DA-11D8-B35A-003065ABFD92@mac.com> References: <200402181729.06202@misha-mx.virtual-estates.net> <20040220072258.GA17579@VARK.homeunix.com> <200402201147.03606@misha-mx.virtual-estates.net> <D4B74A4C-63DA-11D8-B35A-003065ABFD92@mac.com>
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Here's some knobs to try, ie; RAID5: Write Back Cache, Normal Read Ahead, and Direct I/O RAID1: Write Through Cache, Normal Read Ahead, and Direct I/O That picked up my write speeds just enough so it wasn't nearly as bad writing as reading. At 02:27 PM 2/20/2004, you wrote: >On Feb 20, 2004, at 11:47 AM, mi+mx@aldan.algebra.com wrote: >>Also, is the RAID5 writing speed supposed to be _so much_ worse, than >>that of a single disk? > >it's normal for RAID-5 write performance to be slower than that of a bare >drive. RAID filesystems involve tradeoffs between cost, performance, and >reliability. RAID-5 maximizes cost and reliability at the expense of >performance.... > >-- >-Chuck > >_______________________________________________ >freebsd-performance@freebsd.org mailing list >http://lists.freebsd.org/mailman/listinfo/freebsd-performance >To unsubscribe, send any mail to "freebsd-performance-unsubscribe@freebsd.org"
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