docker - Docker aufs和devicemapper目录都存在

Question

我试图清理服务器上的一些空间，发现/var/lib/docker/aufs和/var/lib/docker/devicemapper都存在。

  Usage of /:   86.8% of 78.62GB   Users logged in:        0
ncdu 1.10 ~ Use the arrow keys to navigate, press ? for help
--- /var/lib/docker ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
                        /..
   35.3GiB [##########] /aufs
   21.4GiB [######    ] /devicemapper
  810.5MiB [          ] /tmp
  188.3MiB [          ] /containers
   96.3MiB [          ] /init
   29.4MiB [          ]  linkgraph.db
   13.4MiB [          ] /graph
    1.2MiB [          ] /execdriver
  108.0KiB [          ] /volumes
   36.0KiB [          ] /vfs
    8.0KiB [          ] /trust
    8.0KiB [          ]  repositories-aufs
    4.0KiB [          ]  repositories-devicemapper

由于似乎一次只能启用一个，所以我有些困惑。当我运行 docker info时，好像启用了devicemapper而不是aufs:

root@bsc:/var/lib/docker/aufs# docker info
Containers: 115
Images: 326
Storage Driver: devicemapper
 Pool Name: docker-253:1-1318913-pool
 Pool Blocksize: 65.54 kB
 Backing Filesystem: extfs
 Data file: /dev/loop0
 Metadata file: /dev/loop1
 Data Space Used: 15.67 GB
 Data Space Total: 107.4 GB
 Data Space Available: 10.96 GB
 Metadata Space Used: 25.83 MB
 Metadata Space Total: 2.147 GB
 Metadata Space Available: 2.122 GB
 Udev Sync Supported: false
 Data loop file: /var/lib/docker/devicemapper/devicemapper/data
 Metadata loop file: /var/lib/docker/devicemapper/devicemapper/metadata
 Library Version: 1.02.82-git (2013-10-04)
Execution Driver: native-0.2
Kernel Version: 3.13.0-36-generic
Operating System: Ubuntu 14.04.2 LTS
CPUs: 4
Total Memory: 7.798 GiB
Name: bsc
ID: HCND:CWXF:XVRP:OZ45:HDHS:LLNO:Z2T3:L4XZ:UE6N:AOTW:A5C5:PZ76

这是否意味着删除 /var/lib/docker/devicemapper目录是安全的？

Answer 1

看起来您的docker曾经使用aufs作为存储后端，但切换到了devicemapper。 (可能是由于升级了docker包导致的)

如果您(或您的包管理器)更改了存储后端，则docker不会将现有的容器和/或镜像转换为使用新的存储后端。因此，您将看到一个空的容器和图像列表。但是文件将保留在那里。因此，只要您不需要aufs目录中的容器和图像，就可以删除它。