Creating EXT4 Volumes with Linux
Summary
Storage compatibility issues may arise when implementing different OS versions of Linux.
Information
When formatting an ext4 volume, it is best practice to ensure that the Linux kernel version of the machine formatting the volume matches the kernel version of the nodes using the volume.
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The EXT2/3/4 file system has an extensible on-disk format. New features can be added to the file system, but only newer versions of Linux will understand them.
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If an older version of Linux tries to open a file system that has new on-disk format features that it does not understand, it will refuse to do so.
The tools to create/repair/modify EXT2/3/4 file systems (mkfs, fsck, resize, label, etc.) come in a package called “e2fsprogs“. RHEL7/CentOS7 include “e2fsprogs“ version 1.42. Ubuntu 20.04 and RHEL8 include “e2fsprogs“ 1.45. A new feature called “metadata_csum“ was added to EXT2/3/4, and first appeared in “e2fsprogs“ 1.43. Creating an EXT4 file system using “mke2fs“ from “e2fsprogs“ 1.45 (RHEL8/Ubuntu 20.04) will enable “metadata_csum“ by default. The “resize2fs“ tool version 1.42 (from RHEL7/CentOS7) will refuse to operate on a file system that has “metadata_csum“ enabled, because it does not understand that feature.