From owner-freebsd-current@FreeBSD.ORG Tue Sep 30 16:54:33 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0648816A4BF for ; Tue, 30 Sep 2003 16:54:33 -0700 (PDT) Received: from odin.ac.hmc.edu (Odin.AC.HMC.Edu [134.173.32.75]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3800843FE9 for ; Tue, 30 Sep 2003 16:54:32 -0700 (PDT) (envelope-from brdavis@odin.ac.hmc.edu) Received: from odin.ac.hmc.edu (IDENT:brdavis@localhost.localdomain [127.0.0.1]) by odin.ac.hmc.edu (8.12.9/8.12.3) with ESMTP id h8UNsKDH022958; Tue, 30 Sep 2003 16:54:20 -0700 Received: (from brdavis@localhost) by odin.ac.hmc.edu (8.12.9/8.12.3/Submit) id h8UNsKQ1022957; Tue, 30 Sep 2003 16:54:20 -0700 Date: Tue, 30 Sep 2003 16:54:20 -0700 From: Brooks Davis To: Kevin Oberman Message-ID: <20030930235420.GA21866@Odin.AC.HMC.Edu> References: <20030930202715.C94686@ganymede.hub.org> <20030930234430.BF3905D07@ptavv.es.net> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="3MwIy2ne0vdjdPXF" Content-Disposition: inline In-Reply-To: <20030930234430.BF3905D07@ptavv.es.net> User-Agent: Mutt/1.5.4i X-Virus-Scanned: by amavisd-milter (http://amavis.org/) on odin.ac.hmc.edu cc: freebsd-current@freebsd.org cc: Lukas Ertl Subject: Re: Improvements to fsck performance in -current ...? X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 30 Sep 2003 23:54:33 -0000 --3MwIy2ne0vdjdPXF Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Sep 30, 2003 at 04:44:30PM -0700, Kevin Oberman wrote: > > Date: Tue, 30 Sep 2003 20:28:20 -0300 (ADT) > > From: "Marc G. Fournier" > >=20 > > On Wed, 1 Oct 2003, Lukas Ertl wrote: > >=20 > > > > are either of these enhancements back-patchable to the 4.x fsck, or= do > > > > they require some non-4.x compatible changes to work? > > > > > > It's not just the fsck application itself, background fsck basically = needs > > > file system snapshots, which are only available on UFS2, and I'm not = sure > > > if they can be backported to UFS1 at all. > >=20 > > Ah, okay, so when I move my servers to 5.x, then I'm going to need to > > reformat the systems from scratch, else I lose some serious improvements > > ... is there a list somewhere of what UFS2 has over UFS1? "file system > > snapshots", is that similar to journalling? >=20 > I think this is wrong. I have seen no issue in snapshots or background > fsck with UFS1 volumes. >=20 > And, if you mean "jounalling" as in jfs, no. As I understand it, > snapshot is an atomic capture of the file system metadata which allows > fsck to analyze and repair it on an active file system. (Note: This > only applies to softupdate enabled systems as softupdates assure a > level of consistency in the metadata that assures that fsck will not > make changes to active file space on the file system. >=20 > To get to UFS2, you must newfs the partition. I don't know of nay > other way. The basic improvement in UFS2 is the expansion of many > fields to 64 bits to allow for much larger structures. While newfs in > V5.1 and CURRENT defaults to UFS2, there are no problems continuing to > run UFS1 file systems. UFS2 also allocates less inodes at newfs time and instead adds them on demand so you have less of them to check when you don't have any files using them. > Finally, I don't think there is any issue any longer with using soft > updates on /. The only reason that root did not default to SU under V4 > is that SU disks only periodically update free space information and a > small root partition can fill up during an installworld when all of > the files in (especially) /sbin are replaces which requires enough > space to hold two copies of the directory. Under the default partition > sizes in V5, this is really not an issue and all partitions created by > sysinstall under V5 will default to SU, including /. I believe this problem has been fixed. At least that's what I got out of Kirk's talk as BSDCon. If you have a USENIX membership, you can read about UFS2 at: http://www.usenix.org/publications/library/proceedings/bsdcon03/tech/mckusi= ck.html -- Brooks --=20 Any statement of the form "X is the one, true Y" is FALSE. PGP fingerprint 655D 519C 26A7 82E7 2529 9BF0 5D8E 8BE9 F238 1AD4 --3MwIy2ne0vdjdPXF Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.1 (GNU/Linux) iD8DBQE/ehefXY6L6fI4GtQRAqytAKCe76SmM0VTzzySnccVg0sUazw3mgCfSKsZ M3FLlu6U5HO6dZZKG2qk+B0= =u6WK -----END PGP SIGNATURE----- --3MwIy2ne0vdjdPXF--