When a sufficiently large partition (mine's 55G) contains more than one snapshot, a shutdown -h now will not sync the disk. The output of 'syncing disks' never counts down. This works fine with one snapshot ... but not with more. Small partitions (my other partition is 256M) don't appear to exhibit this problem. Fix: None known to me. How-To-Repeat: I create snapshots once per day on both / and /usr on my laptop. If more than one snapshot exists on /usr, this problem occurs.
Responsible Changed From-To: freebsd-bugs->mckusick Assign to snapshot maintainer
Adding to audit trail, from misfiled PR kern/61568: Date: Sun, 18 Jan 2004 22:59:57 -0800 (PST) From: Joseph Scott <joseph@randomnetworks.com> Message-Id: <20040118225309.C21889@randomservers> References: <200401140729.i0E7Ttok003002@beastie.mckusick.com> <20040114160426.T12913@randomservers> The details I mentioned below appears to be about the same as the results in FreeBSD PR kern/58154. I've CC'd the person who submitted that PR, perhaps he now as more details? I've also tried this on a trial install of VMWare 4 on Windows XP. I was able to shutdown several times after a simple install. Took several snapshots and now the shutdown just hangs. The size of the fs doesn't appear to matter (size was mentioned in the PR). So that makes 3 different systems that showed the exact same results. In order to add this additional info I've also CC'd this as a follow up to the PR. On Wed, 14 Jan 2004, Joseph Scott wrote: -> -> On Tue, 13 Jan 2004, Kirk McKusick wrote: -> -> -> Your results are exactly as I would expect. Each new snapshot -> -> needs to scan all the existing snapshots to purge them from -> -> its view (otherwise deleting older snapshots would cause them -> -> to be saved in the next older snapshot and you could never -> -> reclaim the space). The filesystem is not prevented from -> -> running while these purges are in progress, but the system -> -> will be slower because of the extra I/O. -> -> That makes sense. On another snapshot note it appears that -> snapshots are causing problems under FreeBSD 5.2-RELEASE. It took me -> awhile, but it looks like I can now repeat easily. -> -> 1. Install FreeBSD 5.2-RELEASE from CD -> 2. Run 'shutdown -h now' several times verifing that everything seems ok -> 3. Snapshot a fs a couple of times (2 caused this to happen for me) -> 4. Run 'shutdown -h now' and the system hangs at this line: -> -> syncing disks, buffers remaining... -> -> 5. System requires a hard reset -> -> I've tried this now several times on two different systems with -> exactly the same results each time. This was tested on right after -> completing an install of FreeBSD 5.2-RELEASE, the system was completely -> idle and not being used for anything else. Even after rm'ing the snapshot -> files the shutdown would complete, but with errors which cause fsck's to -> be run when the system comes back up. -> -> This also seems to work with 'shutdown -r now', but it may require -> more than two snapshots to see the problem in that case. -- Joseph Scott http://www.randomnetworks.com/joseph/blog/contact.php
Adding to audit trail, from misfiled PR kern/61581: Date: Mon, 19 Jan 2004 09:05:52 -0500 From: David Gilbert <dgilbert@dclg.ca> Message-Id: <16395.58432.40577.277834@canoe.dclg.ca> Subject: pending/61581: Re: FreeBSD 5.x filesystem snapshots, FreeBSD PR kern/58154 References: <200401140729.i0E7Ttok003002@beastie.mckusick.com> <20040114160426.T12913@randomservers> <20040118225309.C21889@randomservers> >>>>> "Joseph" == Joseph Scott <joseph@randomnetworks.com> writes: Joseph> The details I mentioned below appears to be about the Joseph> same as the results in FreeBSD PR kern/58154. I've CC'd the Joseph> person who submitted that PR, perhaps he now as more details? Joseph> I've also tried this on a trial install of VMWare 4 on Joseph> Windows XP. I was able to shutdown several times after a Joseph> simple install. Took several snapshots and now the shutdown Joseph> just hangs. The size of the fs doesn't appear to matter (size Joseph> was mentioned in the PR). So that makes 3 different systems Joseph> that showed the exact same results. My system is my laptop. I have a script that takes a snapshot at 4 AM on / and /usr. / is 256M nad /usr is 50G. Shutdown hangs when there is more than one snapshot on /usr but it doesn't hang based on any number of snapshots on /. This is 100% repeatable. Remvoing all-but-one /usr snapshot makes shutdowns work just fine. Having more than one makes it hang on the buffers remaining bit. Dave. -- ============================================================================ |David Gilbert, Independent Contractor. | Two things can only be | |Mail: dave@daveg.ca | equal if and only if they | |http://daveg.ca | are precisely opposite. | =========================================================GLO================
Hello, As a side note, i just want to point out that i did not yet encountered this particular problem since 5.3-RELEASE, at least, on my 4 FreeBSD systems. Maybe this PR may be closed, if the original poster confirmed this behaviour for him too? -- -jpeg.
State Changed From-To: open->closed This problem was resolved in 6.0.