How To Expand Rootfs Size

This guide is for those who using OpenMediaVault.
Operation confirmed with OMV for ODROID (OMV_3_0_92_Odroidxu4_4.9.61.img.xz).
Test environments.
- ODROID-XU4 with 64GB eMMC
- ODROID-HC1/HC2 with 16GB MicroSD

OMV for ODROIDs is set to resize rootfs to 7GB only.
Refer to this file.

root@odroidxu4:~# cat /root/.rootfs_resize
14700000s

The system reads this file when its first boot time and resizes the root partition and reboots itself to apply changes.

This is for the reason that some people use the root partition as a storage for their personal data so that would causes system instability.
So the developer team has intended to set the limitations of use root partition by restricting partitions' size.
And for the same reason, you can't create a shared folder with root partition.

But if you want to resize to use full storage of the boot media(MicroSD or eMMC), you can expand the size by following this guide.

It is recommended to update your OMV before proceeding. Move to OMV System - Update Management, and check available updates and update it if there are.

Move to OMV Storage - File Systems menu to check file systems.

It shows only 7GB even I inserted bigger one.

Permit SSH root login to expand that.
Move to OMV Services - SSH menu and switch on Permit root login option, and then save and apply changes.

Open terminal or some SSH access program and login to your OMV as root account.

If it is a first time for login as root account, change password prompt will appear. You have to change that to proceed.

Check partitions again.

target

root@odroidxu4:~# fdisk -l
...
 
Device         Boot    Start       End   Sectors  Size Id Type
/dev/mmcblk0p1          8192    139263    131072   64M 83 Linux
/dev/mmcblk0p2        139264  14700000  14560737    7G 83 Linux
/dev/mmcblk0p3      14700001 120921279 106221279 50.7G 83 Linux
 
...

See the /dev/mmcblk0p2 partition. It is expanded to 14700000 sector as written in /root/.rootfs_resize.
And 106221279 sectors remain, in my case.

Enter the following commands to resize.
Make sure the device name of the boot media that has root partition. Assume that /dev/mmcblk0 is that in this guide.
Do not specify the partition number like /dev/mmcblk0p1.

target

root@odroidxu4:~# fdisk /dev/mmcblk0
 
Welcome to fdisk (util-linux 2.25.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.
 
 
Command (m for help):

Enter the commands like below to re-partitioning your boot media.

target

Command (m for help): p
Disk /dev/mmcblk0: 58.2 GiB, 62537072640 bytes, 122142720 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xd6a661fd
 
Device         Boot    Start       End   Sectors  Size Id Type
/dev/mmcblk0p1          8192    139263    131072   64M 83 Linux
/dev/mmcblk0p2        139264  14700000  14560737    7G 83 Linux
/dev/mmcblk0p3      14700001 120921279 106221279 50.7G 83 Linux
 
 
Command (m for help): d
Partition number (1-3, default 3): 3
 
Partition 3 has been deleted.
 
Command (m for help): d
Partition number (1,2, default 2): 2
 
Partition 2 has been deleted.
 
Command (m for help): n
Partition type
   p   primary (1 primary, 0 extended, 3 free)
   e   extended (container for logical partitions)
Select (default p): p
Partition number (2-4, default 2): 2
First sector (2048-122142719, default 2048): 139264
Last sector, +sectors or +size{K,M,G,T,P} (139264-122142719, default 122142719): 
 
Created a new partition 2 of type 'Linux' and of size 58.2 GiB.
 
Command (m for help): p
Disk /dev/mmcblk0: 58.2 GiB, 62537072640 bytes, 122142720 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0xd6a661fd
 
Device         Boot  Start       End   Sectors  Size Id Type
/dev/mmcblk0p1        8192    139263    131072   64M 83 Linux
/dev/mmcblk0p2      139264 122142719 122003456 58.2G 83 Linux
 
 
Command (m for help): w
The partition table has been altered.
Calling ioctl() to re-read partition table.
Re-reading the partition table failed.: Device or resource busy
 
The kernel still uses the old table. The new table will be used at the next reboot or after you run partprobe(8) or kpartx(8).
 
root@odroidxu4:~#

Case 1. Enter the following commands to apply changes for btrfs format.

target

root@odroidxu4:~# partprobe
Warning: Error fsyncing/closing /dev/mmcblk0rpmb: Input/output error
Warning: Error fsyncing/closing /dev/mmcblk0rpmb: Input/output error
root@odroidxu4:~# btrfs filesystem resize max /
Resize '/' of 'max'
root@odroidxu4:~# sync

Case 2. If you are using ext2, ext3 and ext4 filesystem, enter the following commands to apply.

target

root@odroid:~# resize2fs /dev/<path/of/card> e.g : /dev/mmcblk1p2
resize2fs 1.46.5 (30-Dec-2021)
Filesystem at /dev/mmcblk1p2 is mounted on /; on-line resizing required
old_desc_blocks = 1, new_desc_blocks = 1
The filesystem on /dev/mmcblk1p2 is now 1907456 (4k) blocks long.