Chris Murphy posted on Sun, 20 Apr 2014 14:26:37 -0600 as excerpted: > On Apr 20, 2014, at 2:18 PM, Chris Murphy <[email protected]> wrote: >> What is unknown? > > > /dev/sd[bcd] are 2GB, 3GB, and 4GB respectively. > > [root@localhost ~]# mkfs.btrfs -d raid0 -m raid1 /dev/sd[bcd]
[...] > [root@localhost ~]# mount /dev/sdb /mnt > [root@localhost ~]# btrfs fi show > Label: none uuid: ff85abb0-3398-40a0-b06c-8146cb1bfda0 > Total devices 3 FS bytes used 112.00KiB > devid 1 size 2.00GiB used 787.94MiB path /dev/sdb > devid 2 size 3.00GiB used 315.19MiB path /dev/sdc > devid 3 size 4.00GiB used 775.94MiB path /dev/sdd > > [root@localhost ~]# btrfs fi df /mnt > Data, RAID0: total=921.56MiB, used=256.00KiB > Data, single: total=8.00MiB, used=0.00 > System, RAID1: total=8.00MiB, used=16.00KiB > System, single: total=4.00MiB, used=0.00 > Metadata, RAID1: total=460.75MiB, used=112.00KiB > Metadata, single: total=8.00MiB, used=0.00 > unknown, single: total=16.00MiB, used=0.00 I have no clue /what/ that unknown is. If I didn't see the mkfs.btrfs right above, I'd guess it was filesystem damage of some sort, but with the mkfs.btrfs, and with all three devices very specifically trimmed, I haven't the foggiest. Meanwhile... > [root@localhost ~]# btrfs balance start /mnt > Done, had to relocate 6 out of 6 chunks Count. There's 7 items listed above including unknown. Only 6 of 6 chunks relocated. Conclusion given the below, balance didn't touch that unknown at all! > [root@localhost ~]# btrfs fi show > Label: none uuid: ff85abb0-3398-40a0-b06c-8146cb1bfda0 > Total devices 3 FS bytes used 384.00KiB > devid 1 size 2.00GiB used 0.00 path /dev/sdb > devid 2 size 3.00GiB used 288.00MiB path /dev/sdc > devid 3 size 4.00GiB used 1.19GiB path /dev/sdd > > [root@localhost ~]# btrfs fi df /mnt > Data, single: total=928.00MiB, used=256.00KiB > System, RAID1: total=32.00MiB, used=16.00KiB > Metadata, RAID1: total=256.00MiB, used=112.00KiB > unknown, single: total=16.00MiB, used=0.00 > > > An unknown chunk type here too, exists even after a balance. > Along with a weird allocation different merely due to > balancing an empty file system. As I concluded above, unknown untouched by the balance. The different allocation (raid0 to single) with the empty-filesystem balance is I believe a known issue. Meanwhile, based on those numbers, we have * data single 928 MiB, as one chunk on the 4G (largest) device * system and metadata raid1 32 + 256 = 288 MiB on each of the two largest devices (3G and 4G). * 928 + 256 + 32 = 1216 MiB / 1024 = 1.1875 GiB = show reported usage, 4G device * 256 + 32 = 288 MiB, show reported usage, 3G device * show doesn't seem to report the 16 MiB "unknown" on any of the three Out of curiosity... What does a btrfs balance start -v (verbose) report? What about btrfs scrub start -BdR (no-background, per-device, raw stats)? What about btrfs check? (Obviously without the --repair, so it's read-only) Of course both the command output and the related dmesg, if any, for all the above. And... given the existence of that strange unknown even after the mkfs.btrfs trims... Does a badblocks run (with either -n or -w and -v) turn up anything strange? I'd ask about smartctl -A if it wasn't virtual... -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
