Date: Tue, 3 Apr 2001 14:26:41 -0400 (EDT) From: Robert Watson <rwatson@FreeBSD.org> To: Shawn Rutledge <shawndr@yahoo.com> Cc: freebsd-fs@FreeBSD.org Subject: Re: soft updates and fsck in practice Message-ID: <Pine.NEB.3.96L.1010403142424.7478B-100000@fledge.watson.org> In-Reply-To: <20010403170515.26127.qmail@web2302.mail.yahoo.com>
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Take a look at recent postings by Kirk to freebsd-arch on the topic of background fsck. Over the course of his last few commits, and upcoming commits, he migrates to a model where fsck occurs in two phases: first, a foreground phase which checks for clean flags and soft updates bits, and which is very short for soft updates-enabled file systems. Then, a background fsck phase is initiated for file systems with soft updates to garbage collect any resources in the file system that are disconnected from the namespace, that might be left behind by a crash/failure when soft updates is in use. Initial support for this is now committed to the FreeBSD 5.0-CURRENT tree, but more commits to add support for this to the boot process and fsck are coming soon. Robert N M Watson FreeBSD Core Team, TrustedBSD Project robert@fledge.watson.org NAI Labs, Safeport Network Services On Tue, 3 Apr 2001, Shawn Rutledge wrote: > So, after reading Kirk's Usenix paper and the list > archives, I keep seeing that with Soft Updates you > "shouldn't have to" fsck a filesystem. In theory, you > may just loose a little space over time. > > I've also read Terry Lambert's post (SU/LFS/JFS) > warning against using SU for fast failure recovery > (but may be comfortable with the risks for now, given > the effort in porting LFS or a JFS to FreeBSD -- i.e. > some -vs- none). > > My question: Is anyone running a system using soft > updates and NOT fscking after crashes? Is it even > reasonable in practice? > > Mount refuses to mount a filesystem that isn't marked > clean. If anyone is doing the above, what (non-fsck) > mechanism do you use to mark the filesystems clean? > > I've been experimenting with 4.2-RELEASE but have > current and stable available as well. > > Thanks, > > > ===== > Shawn Rutledge (shawndr@yahoo.com) > > __________________________________________________ > Do You Yahoo!? > Get email at your own domain with Yahoo! Mail. > http://personal.mail.yahoo.com/?.refer=text > > To Unsubscribe: send mail to majordomo@FreeBSD.org > with "unsubscribe freebsd-fs" in the body of the message > To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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