On Mon, Mar 30, 2020 at 04:14:46PM -0600, Chris Murphy wrote: > On Sun, Mar 29, 2020 at 12:42 AM Zygo Blaxell > <ce3g8jdj@xxxxxxxxxxxxxxxxxxxxx> wrote: > > > > 90 seconds sounds about right for the block group scan when mounting on > > a 10TB filesystem. There's a feature called block group tree in kernel > > 5.5 that helps with that: it lays out block group items on disk closer > > together so they can be read in milliseconds. This is an on-disk format > > change, so once you enable that feature, you wouldn't be able to mount > > the filesystem on an older kernel. This can be a problem if your > > sound drivers have regressions. You might want to wait a few kernel > > releases to be sure you don't need to downgrade. > > I'm not seeing anything about block group tree in btrfs/super.c. > > There is block_group_cache_tree but I'm not seeing anything about it > in 'man 5 btrfs' using btrfs-progs 5.4, or in the devel branch. > > So I'm not sure what mount option or btrfstune option this would be, > seems to be automatic? > https://github.com/kdave/btrfs-progs/commit/2eaf862f46b3ccb6b7248a0417ebf7096bc93b80 Sorry, my mistake...it was in one of the misc-next branches, but seems to have been dropped. Maybe not finished yet? > > -- > Chris Murphy >
