On Fri, 2021-01-08 at 00:21 -0700, Chris Murphy wrote: > On Thu, Jan 7, 2021 at 7:52 AM Patrick O'Callaghan > <pocallaghan@xxxxxxxxx> wrote: > > > > On Thu, 2021-01-07 at 21:33 +0800, Qiyu Yan wrote: > > > > and the space usage doesn't seem to have changed. > > > Try using compsize to get space usage? > > > > # compsize /home > > Processed 373221 files, 936531 regular extents (1058479 refs), 155981 > > inline. > > Type Perc Disk Usage Uncompressed Referenced > > TOTAL 98% 1.1T 1.1T 1.0T > > none 100% 1.1T 1.1T 1013G > > zstd 46% 17G 38G 40G > > And are there any new subvolumes you've created below /home? Those are > not subject to -r, the defragment will stop at subvolume boundaries. > Any VM images? If they're nodatacow, they won't compress. And quite a > lot of media files will not compress because they're already > compressed. There is one VM image in its own subvolume, as discussed recently. It's quite large (over 900GB) so that would affect the numbers. > Based on the above numbers I don't think this is as likely the issue > but mention it anyway: Are there any snapshots? 'btrfs fi defragment' > is not snapshot aware and will split up shared extents (makes them > exclusive again, increasing space consumption). No snapshots at the moment. From what you say it seems I would need to consider the tradeoff between using snapshots (e.g. for backup staging) and compression. > Lower priority, more experimentation, purely anecdotal: Using zstd:1 > might result in faster writes to SSD; where zstd:3 (same as zstd) > might result in faster overall writes to HDD. For Fedora 34 the > proposal is 'compress=zstd:1' and that's a bit conservative but also > is low hanging fruit with the biggest gain for the effort. Folks who > don't care about performance or want to use this for archives can > experiment with even higher values. I tend to use zstd:7 on backups. > It does get quite slow eventually, around 11 or higher. But zstd is > fairly invariant to compression level on reads, as in I doubt anyone > can tell a difference on read between a file that was compressed with > 1 vs 9, and maybe not notice 15 unless they were paying attention or > timing it. OK, thanks. poc _______________________________________________ users mailing list -- users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to users-leave@xxxxxxxxxxxxxxxxxxxxxxx Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/users@xxxxxxxxxxxxxxxxxxxxxxx
