Using large file systems with several terabytes of data is quite common. Usually system administrators use well-known file systems like ext4, xfs, zfs or newcomers like btrfs. Even ext4, the more or less standard Linux file system, supports up to 10 EiB of data and is marked as stable since Kernel 2.6.28 (release in December 2008). Increasing volumes beyond 16 TiB shouldn’t be a problem.

In the case of ext4 this is only true if the file system was explicitly created with the 64bit feature enabled, which isn’t the default on recent Linux distributions like Ubuntu 16.04. Without 64-bit support your ext4 volumes are limited to 16TiB of data. The 64bit feature is enabled by default since e2fsprogs >= 1.43, but this version isn’t packed for many Linux distributions yet.

 

Fortunately converting a 32-bit ext4 volume to 64-bit is supported since e2fsprogs >= 1.43. A online conversion is not possible.


  1. download and compile e2fsprogs, at least version 1.43
    $ git clone -b v1.43 https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git e2fsprogs
    $ cd e2fsprogs
    $ ./configure
    $ make
    $ cd resize2fs
    $ ./resize2fs
    
  2. unmount the file system
  3. run fsck and repair your file system
  4. run resize2fs with the -b flag to enable the 64bit feature
    $ resize2fs -b /dev/my-block-device
    
  5. check if 64bit feature is enabled
    $ tune2fs -l /dev/my-block-device
    

Depending on your number of inodes the file system check and the conversion to 64-bit can took a lot of time. For resizing or running a file system check you should use at least the latest minor release of e2fsprogs of 1.42.x


For a more detailed information, just have a quick look into the Release notes of e2fsprogs and on AskUbuntu.
Achim Ledermueller

Autor: Achim Ledermueller

Der Exil Regensburger kam 2012 zu NETWAYS, nachdem er dort sein Wirtschaftsinformatik Studium beendet hatte. In der Managed Services Abteilung ist unter anderem für die Automatisierung des RZ-Betriebs und der Evaluierung und Einführung neuer Technologien zuständig.