Am 15.08.2015 um 20:24 schrieb Георгий Стариков:
how?
as i see, discard is disabled...
# cat /sys/block/sdc/bcache/discard
0
# ./bcache-status -s | grep Discard
Discard? False
OK sorry. I've only seen exactly this issue after reboot with discard
enabled.
Sorry.
Stefan
2015-08-15 21:12 GMT+03:00 Stefan Priebe - Profihost AG <s.priebe@xxxxxxxxxxxx>:
Disable discard ;-) no fix available.
Stefan
Excuse my typo sent from my mobile phone.
Am 15.08.2015 um 19:54 schrieb Георгий Стариков <gstarikov@xxxxxxxxx>:
Hi!
I lost bcache device after a reboot and dmesg contains the following:
[ 26.991085] bcache: prio_read() bad csum reading priorities
[ 26.991088] bcache: prio_read() bad magic reading priorities
[ 26.991425] attempt to access beyond end of device
[ 26.991428] sdc: rw=48, want=3405010361836132352, limit=468862128
[ 26.991430] bcache: error on 4ca0fbc9-d20b-4a3d-bbd1-38d9a5810c27:
accessing priorities,
disabling caching
how to fix it?
i am using the following fix (recreate cache device with the old cuid)
and it works till next reboot.
# bcache-super-show /dev/sdc
sb.magic ok
sb.first_sector 8 [match]
sb.csum F19B35ED4C357841 [match]
sb.version 3 [cache device]
dev.label (empty)
dev.uuid 7dddbf16-ca58-48e3-82d8-da47ae7726dc
dev.sectors_per_block 1
dev.sectors_per_bucket 1024
dev.cache.first_sector 1024
dev.cache.cache_sectors 468860928
dev.cache.total_sectors 468861952
dev.cache.ordered yes
dev.cache.discard no
dev.cache.pos 0
dev.cache.replacement 0 [lru]
cset.uuid 4ca0fbc9-d20b-4a3d-bbd1-38d9a5810c27
# make-bcache -C --cset-uuid 4ca0fbc9-d20b-4a3d-bbd1-38d9a5810c27 /dev/sdc
Already a bcache device on /dev/sdc, overwrite with --wipe-bcache
make-bcache -C --wipe-bcache --cset-uuid
4ca0fbc9-d20b-4a3d-bbd1-38d9a5810c27 /dev/sdc
Device /dev/sdc already has a non-bcache superblock, remove it using
wipefs and wipefs -a
# wipefs -a /dev/sdc
# make-bcache -C --wipe-bcache --cset-uuid
4ca0fbc9-d20b-4a3d-bbd1-38d9a5810c27 /dev/sdc
UUID: f7d97543-69ea-4636-a4ff-ab925ab5abdd
Set UUID: 4ca0fbc9-d20b-4a3d-bbd1-38d9a5810c27
version: 0
nbuckets: 457873
block_size: 1
bucket_size: 1024
nr_in_set: 1
nr_this_dev: 0
first_bucket: 1
# echo /dev/sdc > /sys/fs/bcache/register
dmesg:
[42999.742342] bcache: run_cache_set() invalidating existing data
[42999.900046] bcache: bch_cached_dev_attach() Caching md0 as bcache0
on set 4ca0fbc9-d20b-4a3d-bbd1-38d9a5810c27
[42999.900067] bcache: register_cache() registered cache device sdc
[43002.019693] EXT4-fs (bcache0): recovery complete
[43002.043362] EXT4-fs (bcache0): mounted filesystem with ordered data
mode. Opts: discard,errors=remount-ro
and final steps:
# echo writethrough > /sys/block/bcache0/bcache/cache_mode
# echo 128k > /sys/block/bcache0/bcache/sequential_cutoff
# ./bcache-status -s
--- bcache ---
Device /dev/bcache0 (251:0)
UUID 4ca0fbc9-d20b-4a3d-bbd1-38d9a5810c27
Block Size 0.50KiB
Bucket Size 512.00KiB
Congested? False
Read Congestion 2.0ms
Write Congestion 20.0ms
Total Cache Size 223.57GiB
Total Cache Used 2.24GiB (0%)
Total Cache Unused 221.34GiB (99%)
Dirty Data 0B (0%)
Evictable Cache 223.57GiB (100%)
Replacement Policy [lru] fifo random
Cache Mode [writethrough] writeback writearound none
Total Hits 139 (3%)
Total Misses 3816
Total Bypass Hits 0
Total Bypass Misses 0
Total Bypassed 0B
--- Backing Device ---
Device /dev/md0 (9:0)
Size 5.46TiB
Cache Mode [writethrough] writeback writearound none
Readahead 0
Sequential Cutoff 128.00KiB
Merge sequential? False
State clean
Writeback? True
Dirty Data 0B
Total Hits 139 (3%)
Total Misses 3816
Total Bypass Hits 0
Total Bypass Misses 0
Total Bypassed 0B
--- Cache Device ---
Device /dev/sdc (8:32)
Size 223.57GiB
Block Size 0.50KiB
Bucket Size 512.00KiB
Replacement Policy [lru] fifo random
Discard? False
I/O Errors 0
Metadata Written 1.60MiB
Data Written 19.20MiB
Buckets 457873
Cache Used 2.24GiB (0%)
Cache Unused 221.34GiB (99%)
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