resize2fs: Bad magic number in super-block while trying to open

Question

I am trying to resize a logical volume on CentOS7 but am running into the following error:

resize2fs 1.42.9 (28-Dec-2013)
resize2fs: Bad magic number in supe         


        

Answer 1

How to resize root partition online :  

1)  [root@oel7 ~]# df -h  
Filesystem                         Size  Used Avail Use% Mounted on  
/dev/mapper/root_vg-root           5.0G  4.5G  548M  90% /

2)   

PV /dev/sda2   VG root_vg     lvm2 [6.00 GiB / 0    free]

as here it shows that there is no space left on root_vg volume group, so first i need to extend VG 

3)  
[root@oel7 ~]# vgextend root_vg /dev/sdb5  

  Volume group "root_vg" successfully extended

4)  

[root@oel7 ~]# pvscan  
    PV /dev/sda2   VG root_vg     lvm2 [6.00 GiB / 0    free]  
    PV /dev/sdb5   VG root_vg     lvm2 [2.00 GiB / 2.00 GiB free]

5)  Now extend the logical volume   

[root@oel7 ~]# lvextend -L +1G /dev/root_vg/root  

  Size of logical volume root_vg/root changed from 5.00 GiB (1280 extents) to 6.00 GiB (1536 extents).
  Logical volume root successfully resized  

3)  [root@oel7 ~]# resize2fs /dev/root_vg/root  

resize2fs 1.42.9 (28-Dec-2013)  
resize2fs: Bad magic number in super-block while trying to open /dev/root_vg  /root  
Couldn't find valid filesystem superblock.  

as root partition is not a ext* partiton so , you resize2fs will not work for you.  

4)  to check the filesystem type of a partition 
[root@oel7 ~]# df -Th  
Filesystem                        Type      Size  Used Avail Use% Mounted on  
/dev/mapper/root_vg-root          xfs       6.0G  4.5G  1.6G  75% /  
devtmpfs                          devtmpfs  481M     0  481M   0% /dev  
tmpfs                             tmpfs     491M   80K  491M   1% /dev/shm  
tmpfs                             tmpfs     491M  7.1M  484M   2% /run  
tmpfs                             tmpfs     491M     0  491M   0% /sys/fs  /cgroup
/dev/mapper/data_vg-home          xfs       3.5G  2.9G  620M  83% /home  
/dev/sda1                         xfs       497M  132M  365M  27% /boot  
/dev/mapper/data_vg01-data_lv001  ext3      4.0G  2.4G  1.5G  62% /sybase  
/dev/mapper/data_vg02-backup_lv01 ext3      4.0G  806M  3.0G  22% /backup  

above command shows that root is an xfs filesystem , so we are sure that we need to use xfs_growfs command to resize the partition.

6)  [root@oel7 ~]# xfs_growfs /dev/root_vg/root  
meta-data=/dev/mapper/root_vg-root isize=256    agcount=4, agsize=327680 blks
         =                       sectsz=512   attr=2, projid32bit=1
         =                       crc=0        finobt=0
data     =                       bsize=4096   blocks=1310720, imaxpct=25
         =                       sunit=0      swidth=0 blks
naming   =version 2              bsize=4096   ascii-ci=0 ftype=0
log      =internal               bsize=4096   blocks=2560, version=2
         =                       sectsz=512   sunit=0 blks, lazy-count=1
realtime =none                   extsz=4096   blocks=0, rtextents=0
data blocks changed from 1310720 to 1572864  

[root@oel7 ~]# df -Th  

Filesystem                        Type      Size  Used Avail Use% Mounted on
/dev/mapper/root_vg-root          xfs       6.0G  4.5G  1.6G  75% /