On Sat, Feb 27, 2016 at 10:06:06AM -0800, Liu Bo wrote:

Can you grep this message since btrfs dev scan has a "printf("Scanning for Btrfs filesystems\n");"?
And if a scan failed somehow, it may print an error after this message
and we then know what was happening..

I'm not seeing anything in my console boot log outside of this posted in
my previous message:

Fri Feb 26 14:55:17 2016: raid0d1 (started)...raid0d2 (starting)...
Fri Feb 26 14:55:18 2016: raid0d2 (started)...done.

quoted

I'm looking at my boot:
[  112.063677] BTRFS: device label btrfs_space devid 1 transid 776782 /dev/mapper/raid0d1
[  112.090192] BTRFS info (device dm-6): disk space caching is enabled
[  112.111740] BTRFS: failed to read the system array on dm-6
[  112.160047] BTRFS: open_ctree failed
[  112.269710] BTRFS info (device dm-6): disk space caching is enabled
[  112.291430] BTRFS: failed to read the system array on dm-6
[  112.320104] BTRFS: open_ctree failed

So dm-6 is: raid0d1 -> ../dm-6

btrfs dev scan didn't output any messages from what I can tell, outside
of the dmesg stuff here.

The total messages around that time:
[  110.182362] bcache: bch_journal_replay() journal replay done, 92 keys in 6 entries, seq 8855
[  110.208992] bcache: register_cache() registered cache device dm-4
[  110.236345] bcache: register_bdev() registered backing device dm-1
[  110.316129] bcache: bch_cached_dev_attach() Caching dm-1 as bcache1 on set 0226553a-37cf-41d5-b3ce-8b1e944543a8
[  110.348350] bcache: register_bcache() error opening /dev/md5: device already registered
[  110.445200] Adding 15616764k swap on /dev/mapper/eswap1.  Priority:-1 extents:1 across:15616764k FS
[  111.585812] EXT4-fs (md11): mounted filesystem with ordered data mode. Opts: (null)
[  112.063677] BTRFS: device label btrfs_space devid 1 transid 776782 /dev/mapper/raid0d1
[  112.090192] BTRFS info (device dm-6): disk space caching is enabled
[  112.111740] BTRFS: failed to read the system array on dm-6
[  112.160047] BTRFS: open_ctree failed
[  112.269710] BTRFS info (device dm-6): disk space caching is enabled
[  112.291430] BTRFS: failed to read the system array on dm-6
[  112.320104] BTRFS: open_ctree failed
[  112.332567] BTRFS: device label dshelf1 devid 1 transid 25903 /dev/bcache1
[  112.333076] BTRFS info (device bcache1): disk space caching is enabled
[  112.333077] BTRFS: has skinny extents
[  115.185582] BTRFS: detected SSD devices, enabling SSD mode
[  115.216381] BTRFS: device label dshelf2 devid 1 transid 444834 /dev/mapper/dshelf2
[  115.241607] BTRFS info (device dm-2): disk space caching is enabled
[  115.591923] BTRFS info (device dm-2): bdev /dev/mapper/dshelf2 errs: wr 0, rd 0, flush 0, corrupt 65, gen 0

Marc
-- 
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Microsoft is to operating systems ....
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Home page: http://marc.merlins.org/                         | PGP 1024R/763BE901