Date: Mon, 21 Jan 2002 17:05:28 -0600 From: "Mike Meyer" <mwm-dated-1012086328.e3f4de@mired.org> To: "Richard E. Hawkins" <dochawk@psu.edu> Cc: questions@freebsd.org Subject: Re: spreading system across four fast scsi disks Message-ID: <15436.40632.383947.819624@guru.mired.org> In-Reply-To: <77914840@toto.iv>
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Richard E. Hawkins <dochawk@psu.edu> types: > dual AMD 1900 MP > 2G DDR > sony 21" > buckling spring keyboard with control key where God meant it to Be > 4x 9g cheetah 1500rpm U160 scsi drive > 2x18g cheetah 1500rpm U160 scsi drive > no smoke pellets :( > > Anyway, the FreeBSD installation will run across the 4 small drives, > with the two large drives for catching data as models run. > > But how to divide the four drives? > > I'm assuming that /, /usr, swap, and /home all go on different drives > (and that swap really gets its own drive, or at least stuff that > wouldn't get hit on in high performance operations). Don't give swap it's own drive. If you're really thinking about giving it 9 gig, give it 2.x gig (x should be > 64K of memory so you can get dumps) on all four drives. If you can split the drives across two controllers, even better. > What about /var, though? The purpose of the split is so that the heads > can be in places likely to be used simultaneously. The second sentence is critical. For swap, the system is smart enough to interleave swap across multiple disks. Let it do it's thing. Vinum can do the same kind of thing with data partitions, though you can't boot off of them. > Would anything in / oustside of /usr get touched much while a fortran > program was running? Would /var get touched more than every few > minutes? > > Does it matter anyway? :) > > I assume the program will be on /home (which I figure to give all but a > little of its drive) and relying on libraries (fortran, imsl, etc.) in > /usr. /var gets touched every so often. /usr/ will be where most of your user commands are, and will get read to run them. With your commands on /home, they will be swapped in from there if needed. It's really hard to say what to do with the rest of it without knowing what you're going to be doing with it, though. No, that's wrong - you ought to give it to me :-). For example, the 4x9g cheetas might be 1Gig FS, 2Gig swap, 6Gig /home, with vinum used to strip /home across the four devices, possibly with a a mirror as well. The four fs's would be root, /usr, /usr/src and /usr/obj so that rebuilding the world would scream. <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-questions" in the body of the message
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