bcache

entos7的内核3.10安装后没有/sys/fs/bcache/register,升级后4.4自动出现这个目录

下载

[root@localhost mnt]# git clone https://github.com/g2p/bcache-tools.git
Cloning into 'bcache-tools'...
remote: Counting objects: 498, done.
remote: Total 498 (delta 0), reused 0 (delta 0), pack-reused 498
Receiving objects: 100% (498/498), 106.14 KiB | 89.00 KiB/s, done.
Resolving deltas: 100% (257/257), done.
[root@localhost mnt]# ls
bcache-tools
[root@localhost mnt]# cd bcache-tools/
[root@localhost bcache-tools]# ls
69-bcache.rules  bcache.h           bcache-super-show.8  bcache-test.c  dracut    initramfs      make-bcache.c  probe-bcache.8  README
bcache.c         bcache-register.c  bcache-super-show.c  COPYING        initcpio  make-bcache.8  Makefile       probe-bcache.c
[root@localhost bcache-tools]#

编译

root@localhost bcache-tools]# make
cc -O2 -Wall -g `pkg-config --cflags uuid blkid`   -c -o bcache.o bcache.c
cc -O2 -Wall -g `pkg-config --cflags uuid blkid`    make-bcache.c bcache.o  `pkg-config --libs uuid blkid` -o make-bcache
cc -O2 -Wall -g `pkg-config --cflags uuid blkid`    probe-bcache.c  `pkg-config --libs uuid blkid` -o probe-bcache
cc -O2 -Wall -g -std=gnu99    bcache-super-show.c bcache.o  `pkg-config --libs uuid` -o bcache-super-show
cc -O2 -Wall -g   -c -o bcache-register.o bcache-register.c
cc   bcache-register.o   -o bcache-register
[root@localhost bcache-tools]# make install
install -m0755 make-bcache bcache-super-show    /usr/sbin/
install -m0755 probe-bcache bcache-register        /lib/udev/
install -m0644 69-bcache.rules    /lib/udev/rules.d/
install -m0644 -- *.8 /usr/share/man/man8/
install -D -m0755 initramfs/hook    /usr/share/initramfs-tools/hooks/bcache
install -D -m0755 initcpio/install    /usr/lib/initcpio/install/bcache
install -D -m0755 dracut/module-setup.sh /lib/dracut/modules.d/90bcache/module-setup.sh

注:make时候会报blkid.h: No such file
解决 yum install libblkid-devel

因为我的sdb有数据所以要做一下这一步

[root@localhost bcache-tools]# wipefs -a /dev/sdb /dev/sdc
/dev/sdb: 8 bytes were erased at offset 0x00000200 (gpt): 45 46 49 20 50 41 52 54
/dev/sdb: 8 bytes were erased at offset 0x4fffffe00 (gpt): 45 46 49 20 50 41 52 54
/dev/sdb: 2 bytes were erased at offset 0x000001fe (PMBR): 55 aa
/dev/sdb: calling ioclt to re-read partition table: Success

将sdb作为backing device,也就是HDD的盘符。

[root@localhost bcache-tools]# make-bcache -B /dev/sdb
UUID:            1e957d89-9d85-4011-a582-09a21a320784
Set UUID:        2959a329-b79c-4488-9006-ea3b2143477a
version:        1
block_size:        1
data_offset:        16

将sdc作为cache device,也就是SSD的盘符。后面三个参数可以不要

[root@localhost bcache-tools]# make-bcache -C /dev/sdc -w4k -b1M --writeback
UUID:            cf262569-b799-4e8f-9d06-7a27813005c1
Set UUID:        5049fd85-0353-4177-b8b5-139446e14a49
version:        0
nbuckets:        20480
block_size:        8
bucket_size:        2048
nr_in_set:        1
nr_this_dev:        0
first_bucket:        1

注:
参数意义:

-B: 设置backing device
-C: 设置cache device
-w: block size (hard sector size of SSD),默认是2K,可使用--block=4K代替
-b: bucket size,可以使用--bucket=1M代替

设备注册
格式化完成后需要完成设备的注册,使内核获取设备,可能由于内核版本的问题,在实际配置中发现,会报错,提示无法向register节点写入信息,但是并不影响使用。

[root@localhost bcache]# echo /dev/sdb > /sys/fs/bcache/register
-bash: echo: write error: Invalid argument
[root@localhost bcache]# echo /dev/sdc > /sys/fs/bcache/register
-bash: echo: write error: Invalid argument

设备绑定
完成注册的backing device需要在使用之前绑定到bchache,否则功能无法启用。首先找到完成注册的backing device设备的

[root@localhost bcache]# ls /sys/fs/bcache/
5049fd85-0353-4177-b8b5-139446e14a49  register  register_quiet

那么UUID= 5049fd85-0353-4177-b8b5-139446e14a49

[root@localhost bcache]# echo 5049fd85-0353-4177-b8b5-139446e14a49 > /sys/block/bcache0/bcache/attach

其中使用sdb作为backing device也就是HDD盘,sdc是SSD硬盘

[root@localhost ~]#  lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sdb           8:16   0   20G  0 disk
└─bcache0   252:0    0   20G  0 disk
sr0          11:0    1  680M  0 rom  
sdc           8:32   0   20G  0 disk
sda           8:0    0   20G  0 disk
├─sda2        8:2    0   19G  0 part
│ ├─cl-swap 253:1    0    2G  0 lvm  [SWAP]
│ └─cl-root 253:0    0   17G  0 lvm  /
└─sda1        8:1    0    1G  0 part /boot
[root@localhost ~]#

格式化

[root@localhost ~]# mkfs.ext4 /dev/bcache0

挂载

[root@localhost ~]# mount /dev/bcache0 /mnt
[root@localhost ~]# df
Filesystem          1K-blocks    Used Available Use% Mounted on
devtmpfs              1002136       0   1002136   0% /dev
tmpfs                 1013960       0   1013960   0% /dev/shm
tmpfs                 1013960    8744   1005216   1% /run
tmpfs                 1013960       0   1013960   0% /sys/fs/cgroup
/dev/mapper/cl-root  17811456 5406640  12404816  31% /
/dev/sda1             1038336  266176    772160  26% /boot
tmpfs                  202796       0    202796   0% /run/user/0
/dev/bcache0         20511304   45080  19401268   1% /mnt

完成

其中使用sdb作为backing device,sdc是SSD硬盘

[root@localhost ~]# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sdb           8:16   0   20G  0 disk
└─bcache0   252:0    0   20G  0 disk /mnt
sr0          11:0    1  680M  0 rom  
sdc           8:32   0   20G  0 disk
sda           8:0    0   20G  0 disk
├─sda2        8:2    0   19G  0 part
│ ├─cl-swap 253:1    0    2G  0 lvm  [SWAP]
│ └─cl-root 253:0    0   17G  0 lvm  /
└─sda1        8:1    0    1G  0 part /boot

bcache device状态查看

[root@localhost ~]# bcache-super-show -f /dev/sdc
sb.magic        ok
sb.first_sector        8 [match]
sb.csum            C4ECE29EDDF45C24 [match]
sb.version        3 [cache device]

dev.label        (empty)
dev.uuid        cf262569-b799-4e8f-9d06-7a27813005c1
dev.sectors_per_block    8
dev.sectors_per_bucket    2048
dev.cache.first_sector    2048
dev.cache.cache_sectors    41940992
dev.cache.total_sectors    41943040
dev.cache.ordered    yes
dev.cache.discard    no
dev.cache.pos        0
dev.cache.replacement    0 [lru]

cset.uuid        5049fd85-0353-4177-b8b5-139446e14a49
[root@localhost ~]# bcache-super-show -f /dev/sdb
sb.magic        ok
sb.first_sector        8 [match]
sb.csum            ADE4CA9B43970BA5 [match]
sb.version        1 [backing device]

dev.label        (empty)
dev.uuid        1e957d89-9d85-4011-a582-09a21a320784
dev.sectors_per_block    1
dev.sectors_per_bucket    1024
dev.data.first_sector    16
dev.data.cache_mode    0 [writethrough]
dev.data.cache_state    0 [detached]

cset.uuid        2959a329-b79c-4488-9006-ea3b2143477a
[root@localhost ~]#

停用设备
注销设备:

echo 1 >/sys/fs/bcache//unregister

停用bcache:

echo 1 >/sys/block/bcache0/bcache/stop

擦除磁盘残留数据:

wipefs -a /dev/sdc
wipefs -a /dev/sdb

工作模式
bcache有四种不同工作模式:

writethrough、writeback、writearouond、none

工作模式切换:

echo writeback > /sys/block/sdr/bcache/cache_mode

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