Lines Matching +full:fails +full:- +full:without +full:- +full:test +full:- +full:cd
10 - http://bcache.evilpiepirate.org
11 - http://evilpiepirate.org/git/linux-bcache.git
12 - http://evilpiepirate.org/git/bcache-tools.git
14 It's designed around the performance characteristics of SSDs - it only allocates
22 great lengths to protect your data - it reliably handles unclean shutdown. (It
26 Writeback caching can use most of the cache for buffering writes - writing
33 average is above the cutoff it will skip all IO from that task - instead of
44 You'll need make-bcache from the bcache-tools repository. Both the cache device
47 make-bcache -B /dev/sdb
48 make-bcache -C /dev/sdc
50 make-bcache has the ability to format multiple devices at the same time - if
54 make-bcache -B /dev/sda /dev/sdb -C /dev/sdc
56 bcache-tools now ships udev rules, and bcache devices are known to the kernel
57 immediately. Without udev, you can manually register devices like this::
66 slow devices as bcache backing devices without a cache, and you can choose to add
76 /dev/bcache/by-uuid/<uuid>
77 /dev/bcache/by-label/<label>
85 You can also control them through /sys/fs//bcache/<cset-uuid>/ .
92 ---------
99 echo <CSET-UUID> > /sys/block/bcache0/bcache/attach
103 /dev/bcache<N> device won't be created until the cache shows up - particularly
117 cache, don't expect the filesystem to be recoverable - you will have massive
121 --------------
123 Bcache tries to transparently handle IO errors to/from the cache device without
128 - For reads from the cache, if they error we just retry the read from the
131 - For writethrough writes, if the write to the cache errors we just switch to
135 - For writeback writes, we currently pass that error back up to the
136 filesystem/userspace. This could be improved - we could retry it as a write
139 - When we detach, we first try to flush any dirty data (if we were running in
140 writeback mode). It currently doesn't do anything intelligent if it fails to
145 --------------
150 to force it to run without the cache::
156 if it's absent, or registration fails for some reason, you can still
157 start your bcache without its cache, like so::
166 host:/sys/block/md5/bcache# echo 0226553a-37cf-41d5-b3ce-8b1e944543a8 > attach
168 [ 1933.478179] bcache: __cached_dev_store() Can't attach 0226553a-37cf-41d5-b3ce-8b1e944543a8
172 or disappeared and came back, and needs to be (re-)registered::
180 Please report it to the bcache development list: linux-bcache@vger.kernel.org
186 D) Recovering data without bcache:
190 of the backing device created with --offset 8K, or any value defined by
191 --data-offset when you originally formatted bcache with `make-bcache`.
195 losetup -o 8192 /dev/loop0 /dev/your_bcache_backing_dev
200 cache device without loosing data.
207 host:~# wipefs -a /dev/sdh2
213 host:~# make-bcache -C /dev/sdh2
214 UUID: 7be7e175-8f4c-4f99-94b2-9c904d227045
215 Set UUID: 5bc072a8-ab17-446d-9744-e247949913c1
232 host:/sys/block/md5/bcache# echo 5bc072a8-ab17-446d-9744-e247949913c1 > attach
233 … bcache: bch_cached_dev_attach() Caching md5 as bcache0 on set 5bc072a8-ab17-446d-9744-e247949913c1
241 host:~# wipefs -a /dev/nvme0n1p4
247 host:/sys/fs/bcache/b7ba27a1-2398-4649-8ae3-0959f57ba128# ls -l cache0
248 …lrwxrwxrwx 1 root root 0 Feb 25 18:33 cache0 -> ../../../devices/pci0000:00/0000:00:1d.0/0000:70:0…
249 host:/sys/fs/bcache/b7ba27a1-2398-4649-8ae3-0959f57ba128# echo 1 > stop
250 …kernel: [ 917.041908] bcache: cache_set_free() Cache set b7ba27a1-2398-4649-8ae3-0959f57ba128 unr…
254 host:~# wipefs -a /dev/nvme0n1p4
258 G) dm-crypt and bcache
268 fdisk run and re-register a changed partition table, which won't work
279 host:/sys/block/bcache0# cd bcache
280 bash: cd: bcache: No such file or directory
287 bcache: cache_set_free() Cache set 5bc072a8-ab17-446d-9744-e247949913c1 unregistered
295 host:/sys/fs/bcache# ls -l */{cache?,bdev?}
296 …xrwx 1 root root 0 Mar 5 09:39 0226553a-37cf-41d5-b3ce-8b1e944543a8/bdev1 -> ../../../devices/vir…
297 …xrwx 1 root root 0 Mar 5 09:39 0226553a-37cf-41d5-b3ce-8b1e944543a8/cache0 -> ../../../devices/vi…
298 …lrwxrwxrwx 1 root root 0 Mar 5 09:39 5bc072a8-ab17-446d-9744-e247949913c1/cache0 -> ../../../devi…
300 The device names will show which UUID is relevant, cd in that directory
303 host:/sys/fs/bcache/5bc072a8-ab17-446d-9744-e247949913c1# echo 1 > stop
311 ---------------------------
317 - Backing device alignment
321 width using `make-bcache --data-offset`. If you intend to expand your
331 volume to the following data-spindle counts without re-aligning::
335 - Bad write performance
344 - Bad performance, or traffic not going to the SSD that you'd expect
346 By default, bcache doesn't cache everything. It tries to skip sequential IO -
352 writing an 8 gigabyte test file - so you want to disable that::
360 - Traffic's still going to the spindle/still getting cache misses
362 In the real world, SSDs don't always keep up with disks - particularly with
378 - Still getting cache misses, of the same data
390 and there's no other traffic - that can be a problem.
396 Sysfs - backing device
397 ----------------------
400 (if attached) /sys/fs/bcache/<cset-uuid>/bdev*
425 1M, it will round cache miss reads up to that size, but without overlapping
472 Rate in sectors per second - if writeback_percent is nonzero, background
481 Sysfs - backing device stats
507 Sysfs - cache set
510 Available at /sys/fs/bcache/<cset-uuid>
560 Write to this file to shut down the cache set - waits until all attached
570 Sysfs - cache set internal
594 was reused and invalidated - i.e. where the pointer was stale after the read
600 Sysfs - Cache device
606 Minimum granularity of writes - should match hardware sector size.