Date: Fri, 7 Feb 2003 12:40:19 -0800 (PST) From: Garrett Wollman <wollman@lcs.mit.edu> To: freebsd-bugs@FreeBSD.org Subject: kern/48062: mount -o snapshot doesn't work on +100GB disks Message-ID: <200302072040.h17KeJKw012927@freefall.freebsd.org>
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The following reply was made to PR kern/48062; it has been noted by GNATS. From: Garrett Wollman <wollman@lcs.mit.edu> To: "Simson L. Garfinkel" <simsong@nitroba.com> Cc: FreeBSD-gnats-submit@FreeBSD.ORG Subject: kern/48062: mount -o snapshot doesn't work on +100GB disks Date: Fri, 7 Feb 2003 15:30:07 -0500 (EST) <<On Fri, 7 Feb 2003 14:47:30 -0500 (EST), "Simson L. Garfinkel" <simsong@nitroba.com> said: > Greetings. I have successfully used mount -o snapshot on volumes > less than 30Gb, but when I use it on my 150GB volume, the command hangs > and slowly every other process hangs as well. This behavior is > observed on both a RC2 system and on a 5.0-RELEASE system. Well, at least on a 73-gig disk that was convenient to hand, I can't replicate this problem on a quiet system. Creating the snapshot did take some tens of seconds, and it took about ten seconds to delete it again. The process of creating a snapshot requires that all filesystem activity be brought to a temporary halt, so it is not surprising that creating a snapshot on /usr would eventually hang most other processes until it is completed. Please check the wait channels (by starting something like `top' in another window/VT or by using the `ps' command from DDB) to see what states various processes are in. FYI, the exact results for my experiment are: create 39.92 real 0.00 user 1.20 sys remove 8.72 real 0.00 user 0.31 sys The resulting snapshot contained 42221568 bytes of metadata. (Keeping in mind that this filesystem is empty but for the root directory, the directory containing the snapshot, and the snapshot itself.) -GAWollman To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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