How to run fsck on a Synology NAS

First, make sure SSH is enabled under Control Panel… Terminal and SNMP.

Then, you need to login using ssh interface. The syntax is as follows:

ssh root@nas01
or
ssh root@nas-server-ip-here

Once logged in, either login as su or use sudo before each command.

Run the following to find your volume names
df

Run the following and sit tight; reconnect if you’re disconnected
syno_poweroff_task -d

You may have to unmount the volume first
umount /dev/vg1/volume_1

Activate the volume
vgchange -ay

Run e2fsck
e2fsck -Dfttvy -C 0 /dev/vg1/volume_1

Be patient. This can take a long time!

Run the command again to be sure everything is clean.

Reboot.

For serious issues, run the following (it may take hours or days to finish)
e2fsck -ccDfttvy -C 0 /dev/vg1/volume_1