Amazon EC2 m3.large with only 8GB in root volume

Question

I bought a m3.large but when create instance, I only see 8GB, should change that value to 32 GB? I want use this SSD storage for MySQL. and i need it in root partition

Sorry for my english. Thanks.

The instance description:

Instance Type   ECUs    vCPUs   Memory (GiB)    Instance Storage (GiB)  EBS-Optimized Available Network Performance
m3.large        6.5       2         7.5                1 x 32                           -            Moderate

The storage description:

Type        Device          Snapshot        Size (GiB)  Volume Type   IOPS  Delete on Termination
Root        /dev/sda1       snap-67620582       8       standard       N/A    Yes
ephemeral0  /dev/sdb        N/A                N/A        N/A          N/A    N/A

Answer 1

If you want to use it as root partition, you need to launch an instance store version of your AMI.

The SSD volume is corrently mapped to /dev/sdb. You can mount that at any location on your filesystem. Like to /var/mysql.

If you are not using replication, you will loose the data stored on the ephemeral volume if the instance is stopped or fails for any reason.

Answer 2

The 8GB that you see is basically your EBS volume mounted as the root drive.

You can find the instance store version of your AMI just like @datasage suggested or you can simply make a link to where you want to store your mysql files:

$ mkfs.ext4 /dev/sdb  # This creates the filesystem on the ephemeral storage
$ mkdir -p /mnt/sdb
$ mount /dev/sdb /mnt/sdb
$ ln -s /var/lib/mysql /mnt/sdb/mysql

Keep in mind just like @datasage mentioned you will lose all this data once you shutdown the instance since it's ephemeral storage.