Date: Fri, 28 May 2004 01:20:10 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: Ivan Voras <ivoras@fer.hr> Cc: current@freebsd.org Subject: Re: Softupdates a mount option? Message-ID: <20040527232009.GA63479@cicely12.cicely.de> In-Reply-To: <40B60D2E.3050003@fer.hr> References: <40B4ECC8.50808@fer.hr> <20040526202849.GA37162@freebie.xs4all.nl> <40B519DA.7000708@fer.hr> <20040527120819.B8434@gamplex.bde.org> <40B5DE26.4040901@fer.hr> <20040527124512.GV63479@cicely12.cicely.de> <40B5E66F.7000507@fer.hr> <20040527140744.GW63479@cicely12.cicely.de> <40B60D2E.3050003@fer.hr>
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On Thu, May 27, 2004 at 05:45:50PM +0200, Ivan Voras wrote: > Bernd Walter wrote: > > >>>SU makes perfectly sense for swap backed md drives. > >> > >>I always thought the "swap backed" meant the memory is allocated from the > >>same pool as for userland applications, e.g. they only get swapped out if > >>memory is scarce. Is this wrong? > > > > > >You are right, but md(4) doesn't know about the filesystem and therefor > >can't know which blocks have content to keep and which are unused. > >SU now allows files that are deleted quite fast to never touch the > >block device and md never need to write those blocks into swap storage > >as they never got dirty. > > As opposed to the 'async' mode? I think all async mode files get writen sooner or later even if already deleted, but I'm not shure. -- B.Walter BWCT http://www.bwct.de bernd@bwct.de info@bwct.de
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