Dear list,
I'm sorry if this is a dumb n3wb question, but I couldn't find anything
about it, so please bear with me.
I just decided to try BtrFS for the first time, to replace an old ReiserFS
data partition currently on a mdadm mirror. To do so, I'm using two 3 TB
disks that were initially detected as sdd and sde, on which I have a
single large GPT partition, so the devices I'm using for btrfs are sdd1
and sde1.
I created a filesystem on them using RAID1 from the start (mkfs.btrfs -d
raid -m raid1 /dev/sd{d,e}1), and started copying the data from the old
partition onto it during the night. As it happened, I immediately got
reason to try out BtrFS recovery because sometime during the copying
operation /dev/sdd had some kind of cable failure and was removed from the
system. A while later, however, it was apparently auto-redetected, this
time as /dev/sdi, and BtrFS seems to have inserted it back into the
filesystem somehow.
The current situation looks like this:
$ sudo ./btrfs fi show
Label: none uuid: 40d346bb-2c77-4a78-8803-1e441bf0aff7
Total devices 2 FS bytes used 1.64TB
devid 1 size 2.73TB used 1.64TB path /dev/sdi1
devid 2 size 2.73TB used 2.67TB path /dev/sde1
Btrfs v0.20-rc1-56-g6cd836d
As you can see, /dev/sdi1 has much less space used, which I can only
assume is because extents weren't allocated on it while it was off-line.
I'm now trying to remedy this, but I'm not sure if I'm doing it right.
What I'm doing is to run "btrfs fi bal start /mnt &", and it gives me a
ton of kernel messages that look like this:
Feb 12 22:57:16 nerv kernel: [59596.948464] btrfs: relocating block group 2879804932096 flags 17
Feb 12 22:57:45 nerv kernel: [59626.618280] btrfs_end_buffer_write_sync: 8 callbacks suppressed
Feb 12 22:57:45 nerv kernel: [59626.621893] lost page write due to I/O error on /dev/sdd1
Feb 12 22:57:45 nerv kernel: [59626.621893] btrfs_dev_stat_print_on_error: 8 callbacks suppressed
Feb 12 22:57:45 nerv kernel: [59626.621893] btrfs: bdev /dev/sdd1 errs: wr 66339, rd 26, flush 1, corrupt 0, gen 0
Feb 12 22:57:45 nerv kernel: [59626.644110] lost page write due to I/O error on /dev/sdd1
[Lots of the above, and occasionally a couple of lines like these]
Feb 12 22:57:48 nerv kernel: [59629.569278] btrfs: found 46 extents
Feb 12 22:57:50 nerv kernel: [59631.685067] btrfs_dev_stat_print_on_error: 5 callbacks suppressed
This barrage of messages combined with the fact that the rebalance is
going quite slowly (btrfs fi bal stat indicates about 1 extent per minute,
where an extent seems to be about 1 GB; which is several factors slower
than it took to copy the data onto the filesystem) leads me to think that
something is wrong. Is it, or should I just wait 2 days for it to
complete, ignoring the error?
Also, why does it say that the errors are occuring /dev/sdd1? Is it just
remembering the whole filesystem by that name since that's how I mounted
it, or is it still trying to access the old removed instance of that disk
and is that, then, why it's giving all these errors?
Thanks for reading!
--
Fredrik Tolf
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