Re: [systemd-devel] journal fragmentation on Btrfs

On Sat, 22.04.17 15:29, Andrei Borzenkov (arvidj...@gmail.com) wrote: > 18.04.2017 07:27, Chris Murphy пишет: > > On Mon, Apr 17, 2017 at 10:05 PM, Andrei Borzenkov > > wrote: > >> 18.04.2017 06:50, Chris Murphy пишет: > > > What exactly "changes" mean? Write()

Re: [systemd-devel] journal fragmentation on Btrfs

22.04.2017 15:29, Andrei Borzenkov пишет: > 18.04.2017 07:27, Chris Murphy пишет: >> On Mon, Apr 17, 2017 at 10:05 PM, Andrei Borzenkov >> wrote: >>> 18.04.2017 06:50, Chris Murphy пишет: >> > What exactly "changes" mean? Write() syscall? filefrag reported

Re: [systemd-devel] journal fragmentation on Btrfs

18.04.2017 07:27, Chris Murphy пишет: > On Mon, Apr 17, 2017 at 10:05 PM, Andrei Borzenkov > wrote: >> 18.04.2017 06:50, Chris Murphy пишет: > What exactly "changes" mean? Write() syscall? >>> >>> filefrag reported entries increase, it's using FIEMAP. >>> >> >> So far

Re: [systemd-devel] journal fragmentation on Btrfs

On Mon, 17.04.17 21:50, Chris Murphy (li...@colorremedies.com) wrote: > >> Why do I see so many changes to the journal file, once ever 2-5 > >> seconds? This adds 4096 byte blocks to the file each time, and when > >> cow, that'd explain why there are so many fragments. > >> > > > > > > What

Re: [systemd-devel] journal fragmentation on Btrfs

On Mon, 17.04.17 13:49, Chris Murphy (li...@colorremedies.com) wrote: > On Mon, Apr 17, 2017 at 11:27 AM, Andrei Borzenkov > wrote: > > 17.04.2017 19:25, Chris Murphy пишет: > >> This explains one system's fragmented journals; but the other system > >> isn't snapshotting

Re: [systemd-devel] journal fragmentation on Btrfs

On Mon, Apr 17, 2017 at 10:05 PM, Andrei Borzenkov wrote: > strace -p $(pgrep systemd-journal) > > You will not see actual writes as file is memory mapped, but it > definitely does not do any fsync() every so often.

Re: [systemd-devel] journal fragmentation on Btrfs

On Mon, Apr 17, 2017 at 10:05 PM, Andrei Borzenkov wrote: >> I have no idea if it's fsync or what. How can I tell? >> > > strace -p $(pgrep systemd-journal) > > You will not see actual writes as file is memory mapped, but it > definitely does not do any fsync() every so

Re: [systemd-devel] journal fragmentation on Btrfs

On Mon, Apr 17, 2017 at 10:05 PM, Andrei Borzenkov wrote: > 18.04.2017 06:50, Chris Murphy пишет: >>> What exactly "changes" mean? Write() syscall? >> >> filefrag reported entries increase, it's using FIEMAP. >> > > So far it sounds like btrfs allocates new extent on every

Re: [systemd-devel] journal fragmentation on Btrfs

18.04.2017 06:50, Chris Murphy пишет: > On Mon, Apr 17, 2017 at 9:42 PM, Andrei Borzenkov wrote: >> 17.04.2017 22:49, Chris Murphy пишет: >>> On Mon, Apr 17, 2017 at 11:27 AM, Andrei Borzenkov >>> wrote: 17.04.2017 19:25, Chris Murphy пишет: >

Re: [systemd-devel] journal fragmentation on Btrfs

On Mon, Apr 17, 2017 at 9:42 PM, Andrei Borzenkov wrote: > 17.04.2017 22:49, Chris Murphy пишет: >> On Mon, Apr 17, 2017 at 11:27 AM, Andrei Borzenkov >> wrote: >>> 17.04.2017 19:25, Chris Murphy пишет: This explains one system's fragmented

Re: [systemd-devel] journal fragmentation on Btrfs

On Mon, Apr 17, 2017 at 11:27 AM, Andrei Borzenkov wrote: > 17.04.2017 19:25, Chris Murphy пишет: >> This explains one system's fragmented journals; but the other system >> isn't snapshotting journals and I haven't figured out why they're so >> fragmented. No snapshots, and

Re: [systemd-devel] journal fragmentation on Btrfs

Here's an example rotated log (Btrfs, NVMe, no compression, default ssd mount option). As you can see it takes up more space on disk than it contains data, so there's a lot of slack space for some reason, despite /etc/systemd/journald.conf being unmodified and thus Compress=Yes. file:

Re: [systemd-devel] journal fragmentation on Btrfs

17.04.2017 19:25, Chris Murphy пишет: > This explains one system's fragmented journals; but the other system > isn't snapshotting journals and I haven't figured out why they're so > fragmented. No snapshots, and they are all +C at create time > (systemd-journald default on Btrfs). Is it possible

Re: [systemd-devel] journal fragmentation on Btrfs

On Mon, Apr 17, 2017 at 3:57 AM, Lennart Poettering wrote: >> I do manual snapshots before software updates, which means new writes >> to these files are subject to COW, but additional writes to the same >> extents are overwrites and are not COW because of chattr +C. I've

Re: [systemd-devel] journal fragmentation on Btrfs

Am Mon, 17 Apr 2017 16:01:48 +0200 schrieb Kai Krakow : > > We also ask btrfs to defrag the file as soon as we mark it as > > archived... > > This makes sense. And I've learned that journal on btrfs works much > better if you use many small files vs. a few big files. I've

Re: [systemd-devel] journal fragmentation on Btrfs

Am Mon, 17 Apr 2017 11:57:21 +0200 schrieb Lennart Poettering : > On Sun, 16.04.17 14:30, Chris Murphy (li...@colorremedies.com) wrote: > > > Hi, > > > > This is on a Fedora 26 workstation (systemd-233-3.fc26.x86_64) > > that's maybe a couple weeks old and was clean

Re: [systemd-devel] journal fragmentation on Btrfs

On Sun, 16.04.17 14:30, Chris Murphy (li...@colorremedies.com) wrote: > Hi, > > This is on a Fedora 26 workstation (systemd-233-3.fc26.x86_64) that's > maybe a couple weeks old and was clean installed. Drive is NVMe. > > > # filefrag * > system.journal: 9283 extents found > user-1000.journal:

[systemd-devel] journal fragmentation on Btrfs

Hi, This is on a Fedora 26 workstation (systemd-233-3.fc26.x86_64) that's maybe a couple weeks old and was clean installed. Drive is NVMe. # filefrag * system.journal: 9283 extents found user-1000.journal: 3437 extents found # lsattr C-- ./system.journal C--