Date: Mon, 20 May 1996 11:15:31 -0500 (CDT) From: Joe Greco <jgreco@brasil.moneng.mei.com> To: bob@luke.pmr.com (Bob Willcox) Cc: jgreco@brasil.moneng.mei.com, joerg_wunsch@uriah.heep.sax.de, kelly@fsl.noaa.gov, taob@io.org, freebsd-chat@freebsd.org, asami@cs.berkeley.edu Subject: Re: 3 terabytes on one server? (was Re: more than 32 scsi disks on a single machine ?) Message-ID: <199605201615.LAA19554@brasil.moneng.mei.com> In-Reply-To: <199605161938.OAA10398@luke.pmr.com> from "Bob Willcox" at May 16, 96 02:38:43 pm
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> > Now admittedly FreeBSD's fsck is a lot faster :-), but if this really is a > > limitation, it is too bad.. maybe I will go look at it :-) > > I believe you don't understand the way FreeBSD actually handles > this. (Heck, maybe I don't either, but this is what I actually > observe happenning.) Hi, You missed the subtle point, that behaviour is all well and fine, but some of us are smarter than fsck and would like to specify the passes explicitly. I certainly agree that fsck checks filesystems in parallel, it just isn't guaranteed to do it "optimally". Consider the case: you have two non-root disks both with multiple partitions. (hypothetical) sd1e 40MB lots of files sd1f 200MB a few big files sd2e 200MB a few big files sd2f 200MB lots of files I don't know what FreeBSD's behaviour would be. Hopefully it would not try to fsck multiple fs's on the same disk concurrently, but maybe it would! However, an intelligent admin might set up sd1f pass 2 sd2e pass 2 sd1e pass 3 sd2f pass 3 to minimize the amount of time "wasted" waiting. This still isn't totally optimal. The best way to do it might be to fork off a per-disk process and have it sequentially iterate (asynchronously from any other "passes" on other disks) through filesystems on that one disk. Or maybe that's what it already does? :-) ... Joe ------------------------------------------------------------------------------- Joe Greco - Systems Administrator jgreco@ns.sol.net Solaria Public Access UNIX - Milwaukee, WI 414/546-7968
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