Linux Debian bcache 摘要

安裝
apt install bcache-tools

建立資料碟(必須大於快取碟)
make-bcache -B /dev/sdx1

建立快取碟(ram disk 不適用)
make-bcache --block 4k --bucket 2M -C /dev/sdy1

指定 資料碟的快取碟
echo $(bcache-super-show /dev/sdy1|grep cset.uuid|awk '{print $2}') >/sys/block/bcache0/bcache/attach
make-bcache -B /dev/sda /dev/sdb -C /dev/sdc

查詢 bcache 運作狀態
cat /sys/block/bcache0/bcache/state
no cache: 沒有 cache 設備
clean: 正常，cache clean
dirty: 正常，cache 模式 writeback，cache 狀態 dirty
inconsistent: 有問題，cache 及 資料沒有同步

查詢cache 模式
cat /sys/block/bcache0/bcache/cache_mode
[writethrough] writeback writearound none

更改 cache 模式
echo writeback > /sys/block/bcache0/bcache/cache_mode

bcache 裝置顯示
/dev/bcacheN
/dev/bcache/by-uuid/UUID
/dev/bcache/by-label/LABEL

停用設備
echo 1 > /sys/block/sdX/sdX[Y]/bcache/stop

停止快取
echo 1 > /sys/block/sdX/sdX[Y]/bcache/detach

安全移除快取
echo <cache-set-uuid> > /sys/block/bcache0/bcache/detach

釋放已使用裝置
echo 1 > /sys/fs/bcache/<cache-set-uuid>/stop

重新載入 bcache 裝置
partprobe  (apt install parted)
echo /dev/sdX > /sys/fs/bcache/register
echo /dev/sdY > /sys/fs/bcache/register

Force flush of cache to backing device
echo 0 > /sys/block/bcache0/bcache/writeback_percent

相關檔案 /etc/tmpfile.d/bcache.conf
w /sys/block/bcache0/bcache/sequential_cutoff - - - - 1M
w /sys/block/bcache0/bcache/cache_mode        - - - - writeback