Date: Mon, 24 Nov 1997 19:46:10 +0000 (GMT) From: Terry Lambert <tlambert@primenet.com> To: bde@zeta.org.au (Bruce Evans) Cc: bde@zeta.org.au, tlambert@primenet.com, fs@FreeBSD.ORG Subject: Re: ufs slowness Message-ID: <199711241946.MAA18929@usr01.primenet.com> In-Reply-To: <199711241924.GAA27999@godzilla.zeta.org.au> from "Bruce Evans" at Nov 25, 97 06:24:35 am
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> >o Is this a ZBR disk? If not, are you using FreeBSD's > > default settings, which pessimize geometry optimizations > > for these disks? > > Of course it's ZBR. FreeBSD's default settings haven't done any > significant geometry optimizations for several years. Sorry; the IDE-ness didn't make that obvious. [ ... ] > >I'd say the *vast* majority of time spent is in directory operations, > >rather than actual file data reading (ie: I think the hit from going > >to indirect blocks in FFS is small). > > I agree. Perhaps it's just ext2fs hanging on to directory blocks better. Maybe. I don't see how, though. > >I'm also betting that you created the ext2fs by tarring up the > >FFS and untarring it onto the ext2fs. Do the same to recreate an > > I actually used `cp -pR' from ext2fs to ufs. I think you'll find that this is the culprit. You should do an "ls -fF" in a couple of equivalent directories and see the ordering of directories vs. files for thiose directories which contain both. You should find that they aren't identical. I think you are seeing a collision between "depth first" and "breadth first" when you tar up the FFS directory. Terry Lambert terry@lambert.org --- Any opinions in this posting are my own and not those of my present or previous employers.
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