详解Linux中获取全球唯一标示符UUID的方法

uuid(universally unique identifiers),全球唯一标示符.它是一个标识系统中的存储设备的字符串,使其确定系统中的所有存储设备。

为什么要使用uuid？因为系统自动分配的设备名称并非总是一致的,它们依赖于启动时内核加载模块的顺序.相同的名称可能代表不同的硬盘分区.如果每个分区有一个唯一的uuid值,尤其是在grub中的kernel设置,这样就不会发生分区识别混乱的问题.

下面介绍几种方法来获得uuid.

1.最简单的方法就是使用blkid命令,它主要用来对系统的块设备(包括交换分区)所使用的文件系统类型,label,uuid等信息查询. 使用这个命令需要安装e2fsprogs包.

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代码如下:

root@10.1.1.200:~# dpkg -l | grep e2fsprogs
ii e2fsprogs 1.41.3-1 ext2/ext3/ext4 file system utilities
ii libuuid-perl 0.02-4 perl extension for using uuid interfaces as defined in e2fsprogs
root@10.1.1.200:~# blkid
/dev/sda1: uuid="b20e80f1-c88d-4918-9d9b-75cd7906629e" type="ext3"
/dev/sda5: type="swap" uuid="1fb3d17b-b2fe-470d-b39c-f00c4a30efbf"
/dev/sda6: uuid="c7050200-7efb-468c-81d1-a3add309bee1" type="ext3" sec_type="ext2"
/dev/sda7: uuid="934e4e22-3431-4707-8d47-dca47e76f448" type="xfs"
/dev/hioa: uuid="de0af117-ad92-4867-aa21-3e7d423e8864" type="xfs"
root@10.1.1.200:~# blkid /dev/sda1
/dev/sda1: uuid="b20e80f1-c88d-4918-9d9b-75cd7906629e" type="ext3"
root@10.1.1.200:~# cat /etc/blkid.tab
<device devno="0x0801" time="1364787338" uuid="b20e80f1-c88d-4918-9d9b-75cd7906629e" type="ext3">/dev/sda1</device>
<device devno="0x0805" time="1364787338" type="swap" uuid="1fb3d17b-b2fe-470d-b39c-f00c4a30efbf">/dev/sda5</device>
<device devno="0x0806" time="1364787338" uuid="c7050200-7efb-468c-81d1-a3add309bee1" type="ext3" sec_type="ext2">/dev/sda6</device>
<device devno="0x0807" time="1364787338" uuid="934e4e22-3431-4707-8d47-dca47e76f448" type="xfs">/dev/sda7</device>
<device devno="0xfd00" time="1364787338" uuid="de0af117-ad92-4867-aa21-3e7d423e8864" type="xfs">/dev/hioa</device>

2.通过浏览/dev/disk/by-uuid/下的设备文件信息.

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代码如下:

root@10.1.1.200:~# ls -l /dev/disk/by-uuid/
total 0
lrwxrwxrwx 1 root root 10 2013-03-19 11:01 1fb3d17b-b2fe-470d-b39c-f00c4a30efbf -> ../../sda5
lrwxrwxrwx 1 root root 10 2013-03-19 11:01 934e4e22-3431-4707-8d47-dca47e76f448 -> ../../sda7
lrwxrwxrwx 1 root root 10 2013-03-19 11:01 b20e80f1-c88d-4918-9d9b-75cd7906629e -> ../../sda1
lrwxrwxrwx 1 root root 10 2013-03-19 11:01 c7050200-7efb-468c-81d1-a3add309bee1 -> ../../sda6
lrwxrwxrwx 1 root root 10 2013-03-19 11:02 de0af117-ad92-4867-aa21-3e7d423e8864 -> ../../hioa
root@10.1.1.200:~# ls -l /dev/disk/by-uuid/ | grep sda1 | awk '{print $8}'
b20e80f1-c88d-4918-9d9b-75cd7906629e

3.通过vol_id命令查看

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代码如下:

root@10.1.1.200:~# vol_id /dev/sda1
id_fs_usage=filesystem
id_fs_type=ext3
id_fs_version=1.0
id_fs_uuid=b20e80f1-c88d-4918-9d9b-75cd7906629e
id_fs_uuid_enc=b20e80f1-c88d-4918-9d9b-75cd7906629e
id_fs_label=
id_fs_label_enc=
id_fs_label_safe=
root@10.1.1.200:~# vol_id /dev/sda1 | grep 'uuid'
id_fs_uuid=b20e80f1-c88d-4918-9d9b-75cd7906629e
id_fs_uuid_enc=b20e80f1-c88d-4918-9d9b-75cd7906629e、

4.使用tune2fs,,它是linux下文件系统调整工具

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代码如下:

root@10.1.1.200:~# tune2fs -l /dev/sda1
tune2fs 1.41.3 (12-oct-2008)
filesystem volume name: <none>
last mounted on: <not available>
filesystem uuid: b20e80f1-c88d-4918-9d9b-75cd7906629e
filesystem magic number: 0xef53
filesystem revision #: 1 (dynamic)
filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery sparse_super large_file
filesystem flags: signed_directory_hash
default mount options: (none)
filesystem state: clean
errors behavior: continue
filesystem os type: linux
inode count: 1864128
block count: 7442103
reserved block count: 372105
free blocks: 6884819
free inodes: 1712582
first block: 0
root@10.1.1.200:~# tune2fs -l /dev/sda1 | grep 'uuid'
filesystem uuid: b20e80f1-c88d-4918-9d9b-75cd7906629e

这里额外在看下tune2fs一些常用参数:

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代码如下:

root@192.168.2.80:~# tune2fs --help
tune2fs 1.41.3 (12-oct-2008)
tune2fs: invalid option -- '-'
usage: tune2fs [-e errors_behavior] [-g group]

[-i interval[d|m|w]] 文件系统的检查间隔时间,系统在达到时间间隔,自动检查文件系统.
[-j] [-j journal_options] 转换文件系统
[-l] 显示文件系统参数
[-m reserved_blocks_percent] 设置保留的空间百分比
[-o [^]mount_options[,...]] 设置默认加载参数.
[-c max_mounts_count] 表示文件系统在mount次数达到设定后，需要运行fsck检查文件系统。
 
通常如果使用ext3文件系统的话，使用-c 0关掉mount次数达到后的文件系统检查。
禁止强制的文件系统检查：

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代码如下:

root@10.1.1.200:~# tune2fs -i0 -c0 /dev/sda1
tune2fs 1.41.3 (12-oct-2008)
setting maximal mount count to -1
setting interval between checks to 0 seconds

还有一个dump2fs也是文件系统调整的工具.

dump2fs显示当前的磁盘状态:

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代码如下:

root@10.1.1.200:~# dumpe2fs /dev/sda1
filesystem volume name: <none>
last mounted on: <not available>
filesystem uuid: b20e80f1-c88d-4918-9d9b-75cd7906629e
filesystem magic number: 0xef53
filesystem revision #: 1 (dynamic)
filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery sparse_super large_file
filesystem flags: signed_directory_hash
default mount options: (none)
filesystem state: clean
errors behavior: continue
filesystem os type: linux
inode count: 1864128
block count: 7442103
reserved block count: 372105
free blocks: 6884819
free inodes: 1712582
first block: 0
block size: 4096
fragment size: 4096
reserved gdt blocks: 1022
blocks per group: 32768
fragments per group: 32768
inodes per group: 8176
inode blocks per group: 511
filesystem created: fri nov 16 15:36:59 2012
last mount time: tue mar 19 11:02:58 2013
last write time: wed mar 27 14:09:25 2013
mount count: 17
maximum mount count: -1
last checked: fri nov 16 15:36:59 2012
check interval: 0 (<none>)
reserved blocks uid: 0 (user root)
reserved blocks gid: 0 (group root)
first inode: 11
inode size: 256
required extra isize: 28
desired extra isize: 28
journal inode: 8
first orphan inode: 1618875
default directory hash: half_md4
directory hash seed: 3090ccf1-625c-4934-9ec4-be3f74767f98
journal backup: inode blocks
journal size: 128m

 

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代码如下:

group 0: (blocks 0-32767)
primary superblock at 0, group descriptors at 1-2
reserved gdt blocks at 3-1024
block bitmap at 1025 (+1025), inode bitmap at 1026 (+1026)
inode table at 1027-1537 (+1027)
0 free blocks, 8152 free inodes, 2 directories
free blocks:
free inodes: 22, 25, 27-8176
group 1: (blocks 32768-65535)
backup superblock at 32768, group descriptors at 32769-32770
reserved gdt blocks at 32771-33792
block bitmap at 33793 (+1025), inode bitmap at 33794 (+1026)
inode table at 33795-34305 (+1027)
3 free blocks, 8176 free inodes, 0 directories
free blocks: 34309-34311
free inodes: 8177-16352
group 2: (blocks 65536-98303)
block bitmap at 65536 (+0), inode bitmap at 65537 (+1)
inode table at 65538-66048 (+2)
7 free blocks, 8176 free inodes, 0 directories
free blocks: 66049-66055
free inodes: 16353-24528
group 3: (blocks 98304-131071)
backup superblock at 98304, group descriptors at 98305-98306
reserved gdt blocks at 98307-99328
block bitmap at 99329 (+1025), inode bitmap at 99330 (+1026)
inode table at 99331-99841 (+1027)
6 free blocks, 8176 free inodes, 0 directories
free blocks: 99842-99847
free inodes: 24529-32704
group 4: (blocks 131072-163839)
block bitmap at 131072 (+0), inode bitmap at 131073 (+1)
inode table at 131074-131584 (+2)
63 free blocks, 0 free inodes, 0 directories
free blocks: 132074-132079, 133643-133647, 135671, 137739-137743, 139811-139815, 141814-141815, 143879, 145922-145927, 147933-147935, 150022-150023, 15207
1, 154107-154111, 156169-156175, 158202-158207, 160251-160255, 162293-162295
free inodes:
group 5: (blocks 163840-196607)
backup superblock at 163840, group descriptors at 163841-163842
reserved gdt blocks at 163843-164864
block bitmap at 164865 (+1025), inode bitmap at 164866 (+1026)
inode table at 164867-165377 (+1027)
0 free blocks, 8130 free inodes, 0 directories
free blocks:
free inodes: 40881, 40928-49056