Date: Sun, 29 Aug 1999 01:36:56 +0200 From: Bernd Walter <ticso@cicely.de> To: Terry Lambert <tlambert@primenet.com> Cc: Bernd Walter <ticso@cicely.de>, freebsd-fs@FreeBSD.ORG Subject: Re: fs-locking and fs memory copies questions Message-ID: <19990829013655.E27811@cicely8.cicely.de> In-Reply-To: <199908282249.PAA06168@usr01.primenet.com>; from Terry Lambert on Sat, Aug 28, 1999 at 10:49:51PM %2B0000 References: <19990828201723.A27704@cicely8.cicely.de> <199908282249.PAA06168@usr01.primenet.com>
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On Sat, Aug 28, 1999 at 10:49:51PM +0000, Terry Lambert wrote: > This is the problem with growing FS's: the hash fill on the > preexisting cylinger groups will be higher than on the new > cylinder groups, leading to fragmentation. Mmmmm - I can't follow you on this. The existing cg's are prefilled with old files. The new ones are empty after growing. I beleaved ffs would prever the new ones automaticaly because of the super-blocks summary information. Guess I need to look more deeply at the block-searching routines. At least the problems created with that should loose during usage. > > A generic defragger would be a good think to have, if you wanted > to allow shrinking partitions, too. > I already need to move blocks around in case the superblock-summary information needs another frag. It was one of the more difficult things to do there are still some erros left about this - the rest was quite easy. Shrinking is something I don't beleave to get working properly, because that would mean loosing cg's with all their inodes. Moving files to different inodes is generaly a mess for NFS-servers. Another point is that finding the reference for a frag is a real expensive thing to do :( -- B.Walter COSMO-Project http://www.cosmo-project.de ticso@cicely.de Usergroup info@cosmo-project.de To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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