# Single User Mode

Boot the server into ['single user mode'](https://bookstack.b4sed.xyz/link/74#bkmrk-page-title)

B. Once in single user mode, we can look to initiate the fsck

We will first need to check the filesystem type being used:

get the device name:

```
root@test:~# df
Filesystem                        1K-blocks    Used Available Use% Mounted on
tmpfs                                400556    1068    399488   1% /run
/dev/mapper/ubuntu--vg-ubuntu--lv  15371208 7497096   7071504  52% /
tmpfs                               2002776       0   2002776   0% /dev/shm
tmpfs                                  5120       0      5120   0% /run/lock
/dev/sda2                           1992552  256828   1614484  14% /boot
tmpfs                                400552       4    400548   1% /run/user/0
```

In this example, we want to check '/dev/mapper/ubuntu--vg-ubuntu--lv' which is mounted to /.

Check the filesystem type:

```
root@test:~# blkid /dev/mapper/ubuntu--vg-ubuntu--lv
/dev/mapper/ubuntu--vg-ubuntu--lv: UUID="2f1c5c3e-54e0-4edc-9d19-a1f170959479" BLOCK_SIZE="4096" TYPE="ext4"
```

As you can see, in this example the type is ext4.

C. Running the fsck:

The general command structure for running an fsck is as below:

```
##Check for errors (No repair)
fsck.filesystem_type /dev/device_name -o ro

##Check and repair errors
fsck.filesystem_type /dev/device_name
```

In this example, I'm going to run a check and then a repair seperately:

```
##Check for errors (No repair)
fsck.ext4 /dev/mapper/ubuntu--vg-ubuntu--lv -o ro

##Check and repair errors
fsck.ext4 /dev/mapper/ubuntu--vg-ubuntu--lv
```

2\.

3\.