Date: Tue, 23 Jul 2002 18:47:03 -0400 From: "Mark W. Krentel" <krentel@dreamscape.com> To: dillon@apollo.backplane.com Cc: freebsd-stable@FreeBSD.ORG Subject: Re: 4.6-RC: Glacial speed of dump backups Message-ID: <200207232247.g6NMl3533962@dreamscape.com>
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Matthew Dillon wrote: > Dump has always had problems dealilng with live filesystems, and its > even worse now that we can't dump via a buffered block device because > the filesystem state is going to be out of sync from the raw device > whether dump re-reads the inodes or not. So even though dump does try > to re-read inodes to check for changes, it is unlikely that our meager > cache will make things worse then the kernel's buffer cache already > makes them. I asked about this on -hackers last week. In Linux, the 2.4 kernels make it impossible for ext2 dump to always see the correct versions of some files, even if there are no writes during the dump. http://old.lwn.net/2001/0503/a/lt-dump.php3 http://old.lwn.net/2001/0503/a/lt-metadata.php3 Are you saying Freebsd has the same problem? I know that dump will have problems when the file system is changing during the dump, but the Linux problems go far beyond that. I did some simple tests and everything works as I'd expect in Freebsd, although it's easy to make Linux fall over. --Mark To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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