I am running Ubuntu Server 12.04 LTS as the guest operating system.
How many volumes can I attach to an instance? I'm working on a project which will require that each of our customers have their own volume.
Amazon seems to not have dynamic volumes, so we need to create a new volume from a snapshot to grow an existing one. This operation requires server down time and that's unacceptable. This is why we need one volume per client. With a physical server, I'll put a 2TB drive and use quotas, but we don't want to go this way for now.
In fact there is no limit if you stick with Linux (Windows instances are limited to 16 EBS volumes). You may have to change the naming of the devices, then you can get easily up to 24 volumes:
/dev/sdf1 /dev/sdf5 /dev/sdf9 /dev/sdg4 /dev/sdg8 /dev/sdh3
/dev/sdf2 /dev/sdf6 /dev/sdg1 /dev/sdg5 /dev/sdg9 /dev/sdh4
/dev/sdf3 /dev/sdf7 /dev/sdg2 /dev/sdg6 /dev/sdh1 /dev/sdh5
/dev/sdf4 /dev/sdf8 /dev/sdg3 /dev/sdg7 /dev/sdh2 /dev/sdh6
For further information take a look at the docs: Attaching the Volume to an Instance.