Date: Mon, 7 Nov 2005 14:01:04 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-fs@FreeBSD.ORG Subject: Re: UFS2 snapshots on large filesystems Message-ID: <200511071301.jA7D14PT038818@lurza.secnetix.de> In-Reply-To: <Pine.LNX.4.21.0511070002410.8180-100000@shell.dhp.com>
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user <user@dhp.com> wrote: > On Sun, 6 Nov 2005, Eric Anderson wrote: > > [fsck on large file systems taking a long time] > > Can you elaborate ? Namely, how long on the 2GB filesystems ? It depends very much on the file system parameters. In particular, it's well worth to lower the inode density (i.e. increase the -i number argument to newfs) if you can afford it, i.e. if you expect to have fewer large files on the file system (such as multimedia files). On a 250 Gbyte drive of mine, I used newfs with -i 131072. That still leaves enough inodes for about 2 million files, but reduces fsck time significantly. A nice side effect is that it gives you more free space for files, because every inode occupies 256 bytes in UFS2. In this case you I got about 7 Gbyte additional space. > As far as the fsck is concerned, this only happens on an ungraceful > reboot, right ? Right. On a kernel panic, hardware freeze, power failure or similar things. > Assuming a snapshot on a 2GB FS, and assuming no crashes, > no long-wait processes like fsck will ever occur, right ? Right. But creating the snapshot in the first place takes a it of time, depending on the size of the file system. > Any other comments ? Do you experience instability/crashes often on > systems of this nature ? No. I recommend you use 6.0-Release or RELENG_6 (6-stable). Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way. "C is quirky, flawed, and an enormous success." -- Dennis M. Ritchie.
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