Mount as EBS volume inside a EC2 instance

By default, if you provision and attach additional EBS volumes for an EC2 instance, they don’t get mounted by default.

The boot EBS is usually /dev/xvda1. Each additional EBS volume should be /dev/xvdb and so on.

First format the new volume:

sudo mkfs -t ext4 /dev/xvdb

Make a mount mount directory like /data, then mount it with:

sudo mount /dev/xvdb /data

Now you should see the new volume available:

$ df -h
Filesystem      Size  Used Avail Use% Mounted on
devtmpfs        3.9G     0  3.9G   0% /dev
tmpfs           3.9G     0  3.9G   0% /dev/shm
tmpfs           3.9G  432K  3.9G   1% /run
tmpfs           3.9G     0  3.9G   0% /sys/fs/cgroup
/dev/xvda1       20G  8.8G   12G  44% /
tmpfs           798M     0  798M   0% /run/user/1000
/dev/xvdb       7.8G   36M  7.3G   1% /data

Add a line to /etc/fstab to mount on startup:

/dev/xvdb /data ext4 defaults,nofail 0 2

These steps are from multiple places, mainly answers to this question.