If your Synology filesystem was ever created on a 32bit NAS you can not expand your volume beyond 16TB. At least not using the GUI.
Basically we need to convert the filesystem to 64-bit. This can be done using the resize2fs command. Unfortunately DSM ships with an ancient version that doesn`t has the ability to convert to 64 bit.
In this howto, we are going to install a recent version of resize2fs , convert the filesystem to 64-bit and ultimately expand the volume beyond 16TB.
First we need to setup Entware-NG
Go to the Synology Package Center, click on “Settings” on the top right corner and then click on “package sources”.
Add the source http://www.cphub.net (you can choose the name freely, i.e. “CPHub”)
Now close the settings. In the package center on the left go to the “Community” tab.
Find and install “Easy Bootstrap Installer” from QTip.
Install Entware using default settings
Login to SSH and execute the following commands
sudo opkg install resize2fs_1.44.5-1_x64-3.2.ipk
run resize2fs , and verify version 1.44 is installed
Now move the folder off the volume (because we will unmount it in the next step)
rm /opt – removes symbolic link to /volume1/@entware
cd /volume1/@entware && mv * /opt
This script shuts down all Synology services and unmounts the volume(s)
sudo syno_poweroff_task -d
The commands below will all take quite long to finish.
sudo e2fsck -f /dev/vg1000/lv If you don`t like answering all questions manually, hit a once. This will answer yes to all questions.
sudo resize2fs -b /dev/vg1000/lv
Now expand the filesystem:
sudo resize2fs -fpF /dev/vg1000/lv
Expand LVM volume
sudo lvextend -l +100%FREE /dev/vg1000/lv
Reboot the NAS
Thats it! Verify your volume has the right size.