Date: Tue, 3 Mar 98 17:27:49 -0500 From: Barry Lustig <barry@lustig.com> To: freebsd-current@FreeBSD.ORG Subject: Re: Panic with CURRENT & softupdates-240298 Message-ID: <19980303222750.1133.qmail@devious.lustig.com> In-Reply-To: <34FC7EFC.237C228A@whistle.com> References: <Pine.NEB.3.96.980303164538.6994B-100000@shadow.worldbank.org> <34FC7EFC.237C228A@whistle.com>
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<nofill>Is anyone planning on back-porting soft-updates to 2.5.X? barry On Tue, 03 Mar 1998, Julian Elischer wrote: > Alok K. Dhir wrote: > > Mind explaining what soft-updates does? > > > > Soft Updates is a method of keeping track of teh dependencies > within the metadata of a filesystem, so that you can ensure > that at every stage, the on-disk image is consistent. It > includes such techniques as temporarily backing out certain > changes during disk writes, and queuing up a lot > of extra information. > > This seems a lot of work, however the gain is that: > 1/ after a crash fsck is not really required. > (except to recover blocks marked in use but really freed in > the last few seconds of running before the crash) > 2/ The writes are ALL (unles you do a fsync()) done async, > 3/ The dependencies automatically notice things like: > "I'm about to write a file but it's already been deleted" > and cancels the operation. > 4/ metadata operations such as deletion are grouped up and > done in bulk which is WAY faster. > > (that's just a quick start) > > julian > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-current" in the body of the message </nofill> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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