Date: Tue, 24 Jul 2001 18:04:27 -0500 From: Mike Meyer <mwm@mired.org> To: "Steve O'Hara-Smith" <steveo@eircom.net> Cc: freebsd-stable@freebsd.org Subject: Re: Regarding hw.ata.wc="1"...... Message-ID: <15197.65275.625021.305764@guru.mired.org> In-Reply-To: <20010724204131.355a3ae6.steveo@eircom.net> References: <3B5D94E7.4680ACEF@mitre.org> <Pine.BSF.4.21.0107240845420.92951-100000@snafu.adept.org> <20010724093512W.jkh@freebsd.org> <20010724204131.355a3ae6.steveo@eircom.net>
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Steve O'Hara-Smith <steveo@eircom.net> types: > On Tue, 24 Jul 2001 09:35:12 -0700 > Jordan Hubbard <jkh@freebsd.org> wrote: > JH> You want a server, use SCSI drives at the very minimum and some sort > JH> of RAID product on top of that if it's really genuinely a server. The > JH> hardware's cheap enough now that there's simply no excuse for not > JH> taking such steps. Enough said. > OT I know, but I have been seriously considering that since complete > systems are sufficiently cheap these days (especially when built without > RAID or SCSI) that it may make more sense to forgoe the SCSI and RAID in > favour of a complete spare system and use a software mirror (or load > duplication) to keep it available for a hot swap. One benefit of this approach > is that the hardware is on *much* shorter lead times this way because it's all > off the shelf and alternatives are feasible. That's an alternative - one I've actually used - but it doesn't change the logic of whether or not you want to use disk caching, just the parameters. Disk caching trades performance for more reliability in specific circumstances - loss of power to the system. Having a hot spare will add more reliability in a different set of circumstances - one system crashing. What's in the intersection are things that shut down the power to the active machine but not the hot spare, which are normally pretty rare. Parallel power sources will make them more common, but that's a more expensive proposition than just keeping a hot spare. <mike -- Mike Meyer <mwm@mired.org> http://www.mired.org/home/mwm/ Independent WWW/Perforce/FreeBSD/Unix consultant, email for more information. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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