SUMMARY Simple method to convert EXT4 to XFS without data restore

Hello esteemed forum members.

For a specific project, I was asked to test if conversion of EXT4 to XFS could work without data restores on RHEL 7.9.

I did it by using EPEL tool fstransform (available in RHEL repositories).

Maybe this information helps someone else in the future.

Step 1
Install tool from EPEL repository:

$ sudo yum -y install fstransform


Step 2
Check current setup for file system /myfs:

$ uname -a && sudo lsblk -f | awk '$NF=="/myfs" {print $NF,"is file system type",$2}' 
Linux myhost.domain.dom 3.10.0-1160.25.1.el7.x86_64 #1 SMP Tue Apr 13 18:55:45 EDT 2021 x86_64 x86_64 x86_64 GNU/Linux
/myfs is file system type ext4

$ sudo mount | grep myfs
/dev/mapper/myvg-mylv on /myfs type ext4 (rw,noatime,data=ordered)


Step 3
Unmount file system /myfs and run the conversion:

$ sudo umount /myfs

$ sudo fstransform /dev/mapper/myvg-mylv xfs


Step 4
Change file system type in /etc/fstab and remount /myfs:

$ sudo sed -i -e "s#/myfs.*ext4#/myfs xfs#" /etc/fstab

$ sudo mount /myfs

$ uname -a && sudo lsblk -f | awk '$NF=="/myfs" {print $NF,"is file system type",$2}'
Linux myhost.domain.dom 3.10.0-1160.25.1.el7.x86_64 #1 SMP Tue Apr 13 18:55:45 EDT 2021 x86_64 x86_64 x86_64 GNU/Linux
/myfs is file system type xfs

Yes, certainly there are some caveats and backups are important in case something goes wrong.

Regards,

Dusan Baljevic (amateur radio VK2COT)