With the option -O 64bit
(enabled by default in filesystems created today), ext file systems can span 1024 PiB instead of just 16 TiB volumes. You can upgrade your old filesystem to activate this option.
Before you start
- This size of volume must be backed by RAID. Regular disk errors will cause harm otherwise.
- Still, RAID is not a backup. You must have your valuables stored elsewhere as well.
- First resize & verify all surrounding volumes (partition tables, encryption, lvm).
- After making changes to RAID, linux may not immediately acknowledge the new maximum size. Check
$ cat /proc/partitions
, reboot if necessary.
- Use a recent, supported kernel. If in doubt, install all upgrades and reboot.
- Acquire e2fsprogs of at version
1.43
(2016-05-17) or greater
- ✔️
Ubuntu 20.04
(2020-04-23) ships with e2fsprogs 1.45.x
(good!)
- ✔️
Ubuntu 18.04
(2018-04-26) ships with e2fsprogs 1.44.x
(good!)
- ❌
Ubuntu 16.04
(2016-04-21) was released with e2fsprogs 1.42.12
(2014-08-25) - upgrade to a newer release or install a newer version manually (see end of this answer):
Steps for a disk at /dev/mapper/target-device
Step 1: Properly umount
$ sudo umount /dev/mapper/target-device
Step 2: Ensure consistency before starting
$ sudo e2fsck -fn /dev/mapper/target-device
-n
flag means to not make changes. Depending on what caused the errors, letting e2fsck
attempt repair may help.
Step 3: Enable 64bit support in the filesystem
$ sudo resize2fs -b /dev/mapper/target-device
Do consider reading man tune2fs
and man resize2fs
- you may wish to change some other filesystem flags as well. On a typical HDD RAID, this takes 4 minutes of high IO & CPU load.
Step 4: Resize
If you do not pass a size on the command line, resize2fs assumes "grow to all space available" - this is typically what you want.
$ sudo resize2fs -p /dev/mapper/target-device
On a typical HDD RAID, this takes 4 minutes of high IO & CPU load. The -p
flag enables progress bars - but those only display after some initial steps.
Step 5: Check again
$ sudo e2fsck -fn /dev/mapper/target-device
e2fsck of newer versions may suggest to fix timestamps or extent trees. This is not an indication of any serious issue and you may chose to fix it now or later.
If errors occur, do not panic and do not attempt to write to the volume; consult someone with extensive knowledge of the filesystem, as further operations would likely destroy data!
If no errors occur, remount the device:
$ sudo mount /dev/mapper/target-device
$ df -h
Enjoy the new space!
If using ancient versions: Extra steps to enable source package support, download and compile a newer version of e2fsprogs
on older systems:
$ resize2fs
# if this prints version 1.43 or above, continue to step 1
$ sudo apt update
$ sudo apt install git
$ sudo apt build-dep e2fsprogs
$ cd $(mktemp -d)
$ git clone -b v1.44.2 https://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git e2fsprogs && cd e2fsprogs
$ ./configure
$ make
$ cd resize
$ ./resize2fs
# confirm that this prints 1.43 or higher
# use `./resize2fs` instead of `resize2fs` for the rest of the steps
You will not need any non-Ubuntu version of e2fsprogs for continued operation of the upgraded filesystem - the kernel supports those for quite some time now. It is only necessary to initiate the upgrade.
For reference, there is a similar error message mke2fs will print if it is asked to create a huge device with inappropriate options:
$ mke2fs -O ^64bit /dev/huge
mke2fs: Size of device (0x123456789 blocks) is too big to be expressed in 32 bits using a blocksize of 4096.
-n
option, because usually the filesystem should be clean. If its not and you cannot tell why, scaling up might not even be a good idea. Sure, e2fsck often is able to resolve filesystem inconsistencies for you - but how you want to handle such depends on what other options at verifying and recovering your data you have. – anx Jul 28 '21 at 14:11