On Thu, Dec 27, 2018 at 12:14 AM Duncan <1i5t5.duncan@xxxxxxx> wrote: > > Chris Murphy posted on Wed, 26 Dec 2018 17:36:19 -0700 as excerpted: > > > > I'm not really following this. An fs resize is implied by any device > > add, remove or replace command. In the case of replace, it will > > efficiently copy the device being replaced to the designated drive, and > > then once that succeeds resize the file system to reflect the size of > > the replacement device. I'm also confused why devid 4 seems to be > > present before and after your device replace, so I have to wonder if > > your copy paste really worked out as intended? And also, what version of > > kernel and btrfs-progs are you using? > > I thought... yes... > > Just checked the btrfs-replace manpage (v4.19.1) and it says: > > Note > the filesystem has to be resized to fully take advantage of a larger > target device; this can be achieved with btrfs filesystem > resize <devid>:max /path > > So it does *not* auto-resize after the replace. Oops. That's unexpected. > > > Also, I'm not positive on this, and I don't see it mentioned in the > manpage, but I /think/ replace (unlike add/remove) keeps the same devid > for the new device. Also unexpected. > It'd be interesting to see what device usage (as opposed to filesystem > usage) did with the unreachable space in terms of reporting -- maybe it > has that separate line tho I doubt it, but if not does it count it or > not?. But that wasn't posted and presumably the query wasn't run while > in the still-unresized state, and I guess it's a bit late now to get it... I'm not sure, it's one of the commands I almost never use. What is device slack? >From my single device that's handy at this moment, the only item I see in 'device usage' that I don't see in 'filesystem usage' is "device slack". Both 'device usage' and 'filesystem usage' show allocated and unallocated per device. While 'filesystem usage' shows the used portion of allocated, it's per profile, not per chunk. -- Chris Murphy
