Amazon EC2 and EBS disk space problem

Question

I am having a problem reconciling the space available on my EBS volume. According to the AWS console the volume is 50GB and is attached to an instance.

If I ssh to this instance and do a df -h, I get the following output:

Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1              15G   13G  3.0G  81% /
udev                  858M   76K  858M   1% /dev
none                  858M     0  858M   0% /dev/shm
none                  858M   72K  858M   1% /var/run
none                  858M     0  858M   0% /var/lock
none                  858M     0  858M   0% /lib/init/rw

I am pretty new to AWS. I interpret this as "there is a device attached and it has 15GB capacity. Whats more, you're nearly out of space!"

Can anyone point out the cause of the apparent discrepancy between the space advertised in the console and what is displayed on the instance?

Many thanks in advance

S

Saturn

Answer 1

Perhaps the original 15 GB Volume was cloned into a 50 GB volume but then not resized?

Please see this tutorial on how to clone and resize: How to increase disk space on existing AWS EC2 Linux (Ubuntu) Instance without losing data

Hope that helps.

Kenna

Answer 2

Yes, the issue is simple. The volume is only associated with the instance, but not mounted.

Check on the AWS console which drive it is mounted as - most likely /dev/sdf.

Then (on ubuntu):

sudo mkfs.ext3 /dev/sdf
sudo mkdir /ebs
sudo mount /dev/sdf /ebs

The first line formats the volume - using the ext3 file system type. This is pretty standard -- but depending on your usage (e.g. app server, database server, ...) you could also select another one like ext4 or xfs.

The second command creates a mount point and the third mounts it into it. This means that effectively, the new volume will be at /ebs. It should also show up in df now.

Last but not least, maybe also add an entry to /etc/fstab to make it reboot-proof.

Airglow

I can see that df lists the device at /dev/sda1 as 15GB and in the AWS console it says the device is mounted at sda1 and is 50GB – Saturn

That's weird. Is this your root device or another 15 GB EBS vol? – Airglow

It adds more disk space to the instance but it doesnt add to the logical disk space. – Permeate

Simon, I have the same problem, it's showing the wrong size. Any help with this? – Tortola

Answer 3

Here is the simple way...

Assuming that you are using a linux AMI, in your case you have an easy method for increasing the size of the file system:

1) Stop the instance 2) Detach the root volume 3) Snapshot the volume 4) Create a new volume from the snapshot using the new size 5) Attach the new volume to the instance on the same place where the original one was 6) Start the instance, stop all services except ssh and set the root filesystem read only 7) Enlarge the filesystem (using for example resize2fs) and or the partition if needed 8) Reboot

As an alternative you can also launch a new instance and map the instance storage or you can create a new ami combining the two previous steps.

Tessatessellate

Answer 4

Only Rebooting the instance solved my problem

Earlier:

/dev/xvda1       8256952 7837552         0 100% /
udev              299044       8    299036   1% /dev
tmpfs             121892     164    121728   1% /run
none                5120       0      5120   0% /run/lock
none              304724       0    304724   0% /run/shm

Now

/dev/xvda18256952 1062780   6774744  14% /
udev              299044       8    299036   1% /dev
tmpfs             121892     160    121732   1% /run
none                5120       0      5120   0% /run/lock
none              304724       0    304724   0% /run/shm

Freezedrying

Answer 5

The remaining of your space is mounted by default at /mnt.

Mickel

Answer 6

See Resizing the Root Disk on a Running EBS Boot EC2 Instance

Dearman

Answer 7

It is because, "After you increase the size of an EBS volume, you must use file system–specific commands to extend the file system to the larger size. You can resize the file system as soon as the volume enters the optimizing state.", without bouncing an instance.

I was just facing the same issue today, I was able to resolve it,

1. Figure out the type of your file system, $ cat /etc/fstab

2. Follow this AWS doc, that precisely documents the steps to extend the linux Partition/FS after resizing a volume of a EC2 instance.

   Extending a Linux File System After Resizing a Volume

Haematoma

Answer 8

On Ubuntu, for Extend the Filesystem.

To find block device:

blkid

In my case type is TYPE="ext4".

To resize the disk volume:

sudo resize2fs /dev/xvdf

Zygo