tune2fs命令允许系统管理员在Linux ext2、ext3或ext4文件系统上调整、设置、查看文件系统参数。tune2fs -l 只会显示 superblock 上的内容。有时候使用tune2fs命令遇到类似“Couldn't find valid filesystem superblock”这样的错误，这个可能是因为你对该命令的一些细节或参数没有注意的缘故。

 

1：tune2fs -l /dev/xxx  tune2fs -l要跟具体的分区，而不是整个硬盘。否则会出现下面错误：

 

[root@mylnx1 ~]# df -T
Filesystem    Type   1K-blocks      Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
              ext3    41518344  29366024  10009296  75% /
/dev/sda1     ext3      101086     23532     72335  25% /boot
/dev/mapper/VolGroup02-LogVol00
              ext3    82537136  42421272  35923200  55% /u01
/dev/mapper/VolGroup01-LogVol00
              ext3   165107052 140918868  15801216  90% /u02
/dev/mapper/VolGroup03-LogVol00
              ext3   185749492 130321240  45992708  74% /u03
/dev/mapper/VolGroup04-LogVol00
              ext3   123822052  98380964  19151272  84% /u04
/dev/sdg1     ext4   104238720  74221532  24722168  76% /u05
tmpfs        tmpfs     2026460         0   2026460   0% /dev/shm
[root@mylnx1 ~]# tune2fs -l /dev/sda
tune2fs 1.39 (29-May-2006)
tune2fs: Bad magic number in super-block while trying to open /dev/sda
Couldn't find valid filesystem superblock.
[root@mylnx1 ~]# tune2fs -l /dev/sda1  #参数是磁盘分区，而不是对应的磁盘
tune2fs 1.39 (29-May-2006)
Filesystem volume name:   /boot
Last mounted on:          <not available>
Filesystem UUID:          2c1864be-127a-4cf5-98aa-a45affaaee72
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal ext_attr resize_inode dir_index filetype needs_recovery sparse_super
Default mount options:    user_xattr acl
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              26104
Block count:              104388
Reserved block count:     5219
Free blocks:              77538
Free inodes:              26064
First block:              1
Block size:               1024
Fragment size:            1024
Reserved GDT blocks:      256
Blocks per group:         8192
Fragments per group:      8192
Inodes per group:         2008
Inode blocks per group:   251
Filesystem created:       Fri May  8 21:55:36 2015
Last mount time:          Sat Apr 25 14:03:18 2020
Last write time:          Sat Apr 25 14:03:18 2020
Mount count:              21
Maximum mount count:      -1
Last checked:             Sun Apr 30 12:55:19 2017
Check interval:           0 (<none>)
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               128
Journal inode:            8
Default directory hash:   tea
Directory Hash Seed:      3505f19e-b37f-48d2-be11-0cdb80f8fb93
Journal backup:           inode blocks

 

2：如果对磁盘分区做了LVM，那么此时将分区作为tune2fs命令的参数将出现下面错误。

 

[root@mylnx1 ~]# tune2fs -l /dev/sdg1

tune2fs 1.39 (29-May-2006)

tune2fs: Filesystem has unsupported feature(s) while trying to open /dev/sdg1

Couldn't find valid filesystem superblock.

 

正确的姿势应该如下：

 

[root@mylnx1 ~]# pvscan
  PV /dev/sdg1   VG VolGroup06   lvm2 [250.00 GB / 0    free]
  PV /dev/sdh8   VG VolGroup06   lvm2 [39.12 GB / 0    free]
  PV /dev/sdf5   VG VolGroup05   lvm2 [199.97 GB / 0    free]
  ..........................................................




[root@mylnx1 ~]# tune2fs -l /dev/mapper/VolGroup06-LogVol00
tune2fs 1.39 (29-May-2006)
Filesystem volume name:   <none>
Last mounted on:          <not available>
Filesystem UUID:          a04472bb-c43e-45e8-8c6d-179a9ebcf6e8
Filesystem magic number:  0xEF53
Filesystem revision #:    1 (dynamic)
Filesystem features:      has_journal resize_inode dir_index filetype needs_recovery sparse_super large_file
Default mount options:    (none)
Filesystem state:         clean
Errors behavior:          Continue
Filesystem OS type:       Linux
Inode count:              32768000
Block count:              65534976
Reserved block count:     3275949
Free blocks:              48745374
Free inodes:              32767884
First block:              0
Block size:               4096
Fragment size:            4096
Reserved GDT blocks:      1008
Blocks per group:         32768
Fragments per group:      32768
Inodes per group:         16384
Inode blocks per group:   512
Filesystem created:       Fri Jun 29 20:31:12 2018
Last mount time:          Sat Apr 25 14:03:18 2020
Last write time:          Sat Apr 25 14:03:18 2020
Mount count:              1
Maximum mount count:      38
Last checked:             Sat Apr 25 13:56:09 2020
Check interval:           15552000 (6 months)
Next check after:         Thu Oct 22 13:56:09 2020
Reserved blocks uid:      0 (user root)
Reserved blocks gid:      0 (group root)
First inode:              11
Inode size:               128
Journal inode:            8
Default directory hash:   tea
Directory Hash Seed:      9ae513c5-c38c-4b3a-81f6-3746d2c8f23a
Journal backup:           inode blocks

 

3：tune2fs只能用于ext2、ext3、ext4文件类型，不支持其它文件类型

 

文件类型为xfs时。报“Couldn't find valid filesystem superblock.”。注意tune2fs只能用于ext2、ext3、ext4文件类型，对于XFS类型，tune2fs不能解读。

 

[root@KerryDB ~]# df -T
Filesystem              Type     1K-blocks    Used Available Use% Mounted on
/dev/mapper/centos-root xfs       52403200 4412324  47990876   9% /
devtmpfs                devtmpfs   1886508       0   1886508   0% /dev
tmpfs                   tmpfs      1899164       0   1899164   0% /dev/shm
tmpfs                   tmpfs      1899164    8964   1890200   1% /run
tmpfs                   tmpfs      1899164       0   1899164   0% /sys/fs/cgroup
/dev/sda2               xfs        1038336  145936    892400  15% /boot
/dev/mapper/centos-home xfs      430525040 1543444 428981596   1% /home
tmpfs                   tmpfs       379836       0    379836   0% /run/user/0
[root@KerryDB ~]# tune2fs -l /dev/sda2
tune2fs 1.42.9 (28-Dec-2013)
tune2fs: Bad magic number in super-block while trying to open /dev/sda2
Couldn't find valid filesystem superblock.

 

 

tune2fs applies only to ext[2-4] filesystems; not to XFS ones. The "Bad magic number in super-block" simply means that tune2fs doesn't understand the filesystem type. As you noted, the fact that your filesystem can be mounted confirms that it's viable.