Whether installing a new physical hard drive to a server or adding an additional disk to your cloud server or VPS, you’ll need to configure CentOS to be able to use it.
If you need a server to try this out on, we recommend our friends at Linode.
We’re going to assume the drive is connected, so first of all, we need to find it.
First of all, we need to know the naming convention your server is using for drives, and we can find this with the ‘df’ command.
[user@server ~] df Filesystem 1K-blocks Used Available Use% Mounted on /dev/vda2 24733776 2521604 20942668 11% / /dev/vda1 1007512 203260 751824 22% /boot
The two lines above show that this particular server is using the vd* notation, but sd* is also used. Here the primary drive, vda, has two partitions – vda1 and vda2.
We can now use the following command to find other disks:
[user@server ~] ls -1 /dev/[sv]d[a-z] /dev/vda /dev/vdb
We can see both our original disk, vda, and the new disk vdb. Now to create a filesystem the new disk with the ‘mkfs.ext4’ utility.
[user@server ~] sudo mkfs.ext4 /dev/vdb
This will just take a few seconds.
To use the new disk we now need to mount it. When you’ve decided where you want to mount the disk, first create that folder on your server. We’re going to use ‘home2’ for our disk.
[user@server ~] sudo mkdir /home2
We can now mount the disk to that location:
[user@server ~] sudo mount /dev/vdb /home2
Revisiting the df command we can now see that the new disk is mounted.
[user@server ~] df Filesystem 1K-blocks Used Available Use% Mounted on /dev/vda2 24733776 2521604 20942668 11% / /dev/vda1 1007512 203260 751824 22% /boot /dev/vdb 25000000 100 24999900 1% /home2
To ensure the disk is automatically mounted when the server is rebooted, we also need to add it to fstab. Our preferred editor is ‘nano’ so we type
[user@server ~] sudo nano /etc/fstab
We add, to the end of the file, the line:
/dev/vdb /home2 ext4 defaults 0 0
Then CTRL + O to save and CTRL + X to exit.
The disk will now stay mounted after reboot and you can begin using it.