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
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% /
In Centos 7 default filesystem is xfs.
xfs file system support only extend not reduce. So if you want to resize the filesystem use xfs_growfs rather than resize2fs.
xfs_growfs /dev/root_vg/root
Note: For ext4 filesystem use
resize2fs /dev/root_vg/root
After reading about LVM and being familiar with PV -> VG -> LV, this works for me :
0) #df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 824K 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/mapper/fedora-root 15G 2.1G 13G 14% /
tmpfs 1.9G 0 1.9G 0% /tmp
/dev/md126p1 976M 119M 790M 14% /boot
tmpfs 388M 0 388M 0% /run/user/0
1) # vgs
VG #PV #LV #SN Attr VSize VFree
fedora 1 2 0 wz--n- 231.88g 212.96g
2) # vgdisplay
--- Volume group ---
VG Name fedora
System ID
Format lvm2
Metadata Areas 1
Metadata Sequence No 3
VG Access read/write
VG Status resizable
MAX LV 0
Cur LV 2
Open LV 2
Max PV 0
Cur PV 1
Act PV 1
VG Size 231.88 GiB
PE Size 4.00 MiB
Total PE 59361
Alloc PE / Size 4844 / 18.92 GiB
Free PE / Size 54517 / 212.96 GiB
VG UUID 9htamV-DveQ-Jiht-Yfth-OZp7-XUDC-tWh5Lv
3) # lvextend -l +100%FREE /dev/mapper/fedora-root
Size of logical volume fedora/root changed from 15.00 GiB (3840 extents) to 227.96 GiB (58357 extents).
Logical volume fedora/root successfully resized.
4) #lvdisplay
5) #fd -h
6) # xfs_growfs /dev/mapper/fedora-root
meta-data=/dev/mapper/fedora-root isize=512 agcount=4, agsize=983040 blks
= sectsz=512 attr=2, projid32bit=1
= crc=1 finobt=1 spinodes=0 rmapbt=0
= reflink=0
data = bsize=4096 blocks=3932160, imaxpct=25
= sunit=0 swidth=0 blks
naming =version 2 bsize=4096 ascii-ci=0 ftype=1
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 3932160 to 59757568
7) #df -h
Filesystem Size Used Avail Use% Mounted on
devtmpfs 1.9G 0 1.9G 0% /dev
tmpfs 1.9G 0 1.9G 0% /dev/shm
tmpfs 1.9G 828K 1.9G 1% /run
tmpfs 1.9G 0 1.9G 0% /sys/fs/cgroup
/dev/mapper/fedora-root 228G 2.3G 226G 2% /
tmpfs 1.9G 0 1.9G 0% /tmp
/dev/md126p1 976M 119M 790M 14% /boot
tmpfs 388M 0 388M 0% /run/user/0
Best Regards,
I ran into the same exact problem around noon today and finally found a solution here --> Trying to resize2fs EB volume fails
I skipped mounting, since the partition was already mounted.
Apparently CentOS 7 uses XFS as the default file system and as a result resize2fs
will fail.
I took a look in /etc/fstab
, and guess what, XFS was staring me in the face... Hope this helps.
On centos and fedora work with fsadm
fsadm resize /dev/vg_name/root
resize2fs Command will not work for all file systems.
Please confirm the file system of your instance using below command.
Please follow the procedure to expand volume by following the steps mentioned in Amazon official document for different file systems.
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/recognize-expanded-volume-linux.html
Default file system in Centos is xfs, use the following command for xfs file system to increase partition size.
sudo xfs_growfs -d /
then "df -h" to check.