【UUID】
UUID stands for Universally Unique Identifier which helps Linux system to identify a hard drives partition instead of block device file. It’s a 128 bit number used to identify information in computer systems.
【通用命令】
假设需要查询的设备名称为:/dev/sda2
- blkid – 输出块设备的属性信息
# blkid
/dev/sda4: LABEL="/" UUID="b6259d20-c9f1-4fb2-993c-67531525f57f" TYPE="ext3" SEC_TYPE="ext2"
/dev/sda3: TYPE="swap" LABEL="SWAP-sda3"
/dev/sda1: LABEL="/boot" UUID="aae1d246-a597-4b7f-ac61-f2565ebf7f91" SEC_TYPE="ext2" TYPE="ext3"
/dev/sda2: LABEL="/tmp" UUID="42f53841-31e7-4e6e-8280-04914dfdea34" TYPE="ext2"
/dev/sdb2: UUID="ff0e0c3d-5c1d-42aa-b03b-ddc4bd39dac6" TYPE="ext3" SEC_TYPE="ext2"
/dev/vol_group/lvm_ext3_01: UUID="935482ac-7907-44b9-8c76-b9082f23d47d" SEC_TYPE="ext2" TYPE="ext3"
- by-uuid – 输出指向可用卷的链接,软链接名称为对应的UUID
#ls -l /dev/disk/by-uuid
lrwxrwxrwx 1 root root 10 Jul 2 08:32 42f53841-31e7-4e6e-8280-04914dfdea34 -> ../../sda2
lrwxrwxrwx 1 root root 10 Jul 2 08:32 aae1d246-a597-4b7f-ac61-f2565ebf7f91 -> ../../sda1
lrwxrwxrwx 1 root root 10 Jul 2 08:32 b6259d20-c9f1-4fb2-993c-67531525f57f -> ../../sda4
lrwxrwxrwx 1 root root 10 Jul 2 08:32 ff0e0c3d-5c1d-42aa-b03b-ddc4bd39dac6 -> ../../sdb2
- tune2fs – 目前仅仅适用于 ext2/ext3/ext4文件系统
# tune2fs -l /dev/sda2 | grep UUID
Filesystem UUID: 42f53841-31e7-4e6e-8280-04914dfdea34
- dumpe2fs – 目前仅仅适用于 ext2/ext3/ext4文件系统
# dumpe2fs /dev/sda2 | grep UUID
dumpe2fs 1.41.9 (22-Aug-2009)
Filesystem UUID: 42f53841-31e7-4e6e-8280-04914dfdea34
【备注】
上述命令获取到的UUID信息的最终数据源均来源于一个卷的Metadata数据,在Linux系统中我们称存放Metadata数据的区域为superblock,该区域位于一个卷的开始位置,占用一定长度的区域。详情可以参考链接:http://www.linfo.org/superblock
查询一个卷的superblock信息的命令如下:dumpe2fs <volume_name>
# dumpe2fs /dev/sda2 | grep superblock
dumpe2fs 1.39 (29-May-2006)
Primary superblock at 0, Group descriptors at 1-1
Backup superblock at 32768, Group descriptors at 32769-32769
Backup superblock at 98304, Group descriptors at 98305-98305
Backup superblock at 163840, Group descriptors at 163841-163841
Backup superblock at 229376, Group descriptors at 229377-229377
Backup superblock at 294912, Group descriptors at 294913-294913