resize2fs is using to extend the ext4 (x-gvfs) file system on Linux

 Work environment : Running redhat linux server which is having two disk sda and sdb 

/dev/sda has configured lvm (xfs) will all reqular file systems such as /home, /root, /tmp, etc.

/dev/sdb is and additional disk which is 800 GB this was pationined using ext4, and mounted the hole sdb to a file system called /www

now the requirement is to increase the /www size 800 GB to 1.2 TB.  from storage level we have increased the size of the secondary disk sdb -800 GB to 1.2 TB.

after reboot the server # fdisk -l /dev/sdb will reflect the resized size. but mounted file system is not showing updated size.

#df -h /www

/etc/fstab entry we could see the /www got mounted using their disk uuid 

# cat /etc/fstab

/dev/disk/by-uuid/0dkdkfjkkui-bokdjkf-kdjfk-hfueu8r9uf /www auto nosuid,nodev,nofail,x-gvfs-show 0 0

we can check uuid using # blkid

ok coming to the core so now resize the file system size using below command

# resize2fs /dev/sdb

then the block size got resized online basis with complete size get resized. then the # df -h /www size got increased automatically

//some useful command for this artical

# mount -a

# lsblk

NAME                          MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT

sda                             8:0    0   80G  0 disk

├─sda1                          8:1    0    1G  0 part /boot

└─sda2                          8:2    0   79G  0 part

  ├─rhel_-root  253:0    0   15G  0 lvm  /

  ├─rhel_-swap  253:1    0    8G  0 lvm  [SWAP]

  ├─rhel_-home  253:2    0   15G  0 lvm  /home

  ├─rhel_ var  253:3    0   13G  0 lvm  /var

  ├─rhel_-opt   253:4    0   13G  0 lvm  /opt

  ├─rhel_-tmp   253:5    0    8G  0 lvm  /tmp

  └─rhel_spare 253:6    0    7G  0 lvm  /spare

sr0                            11:0    1 1024M  0 rom

//if it was lvm then

# xfs_growfs -d /dev/sdb