How to increase an EBS in size?

EBS volumes cannot be increase or grow directly. But what you can do is create a snapshot on the volume and create a bigger volume out of that volume.

If we want for example to increase a volume from 50GB to 100GB we would do the following:

1) Snapshot the original 50 GB volume. This is best done while the volume is not attached, i.e. the instance it is attached to is shutdown. This is necessary in order to ensure that the data on the volume is consistent. An alternative would be to just stop all writes to it and flush the file-system caches. You can create the snapshop on the volume page in Scalarium.

2) Create a new volume based on that snapshot. Chose the desired, bigger size (100 GB in our example) and the snapshot to base the new volume on. Be careful to chose the correct availability zone. You can only create new volumes from snapshots in the same AZ.

3) Disconnect the original 50 GB volume from the instance. Go to the volume page and edit the volume. Chose no instance in the instance option.

4) Connect the new 100 GB volume to the desired instance. Again do this in the volume page. Also chose the mount point etc.

5) Boot the instance. Volume attachments will only happend during the setup process.

6) Once the instance successfully finished its setup, the new volume is available. You now need to increase/grow the filesystem on the new volume. The new volume is a 1:1 copy of the old bytes. So even though the new volume has 100 GB in space only 50 GB are occupied by a file system. So you have to tell the file system to actually claim the extra space:

  $ xfs_growfs /moint/point/of/volume

Done