Volumes

Best practice dictates that content and databases should never reside on the system root volume.  Stratosphere system volumes are of fixed length and cannot be extended.  If the system volume runs out of space because content or data grows beyond the disk's capacity, you may experience problem with your VM.  Stratosphere therefore allows you to provision up to six additional volumes to expand your capacity, preserving the root volume for the exclusive use of the operating system.

Creating volumes

You can create new data disk volumes which can be attached to virtual machines as extra storage.  In order to create a new volume, from the left panel, go through the "Volumes" page under the "Storage" tab and click on the "New Volume" button. 


Volumeview01

You will be prompted for the availability zone where the new volume will reside. Once selected, you will then be prompted for a name.  Select the desired volume size by sliding the button.  


Diskofferings

Each virtual machine automatically comes with a root volume dedicated to the operating system. The size of this volume depends on the type of virtual machine (Linux or Windows) and the template selected. When provisioning a virtual machine, you can optionally add an additional data volume.  Clicking on the up/down arrow will open a drop down box with a list of disk offerings.

Diskofferings2

After your virtual machine is created, you can addition additional volumes as required.  

You can select different volume sizes by clicking on the up/down arrow on the "Disk Offering" line.

Note:  There is a limit of 11 volumes per virtual machine: 1 root disk and up to 10 data disks.  If your virtual machine has already reached its limit, you will be presented with a message like the following:
Volumelimitreached

Attaching volumes

To use a data disk volume you will need to attach it to a virtual machine.  From the "Volumes" page, click the Attachbutton button for that volume.  You will be prompted to select a virtual machine to attach the volume to. You will only be available to attach the volume to virtual machines that are in the same zone.

Volattach

Volumes may also be attached directly from a virtual machine. When attaching a volume to the virtual machine you will be presented with a list of valid volumes available to attach.

Note:  Sometimes, the volume will not attach to a running instance. This could happen if your instance does not have the correct PV drivers installed.  Should this happen, you can can attach the volume to the instance if it is first stopped.

Note:
 Newly attached volumes may or may not automatically appear in you disk management utility, depending upon how well your OS does PnP. You may have to manually scan for the newly attached volume from your OS. 

Detaching volumes

You can detach a volume from a virtual machine by clicking on the Detachbutton button for that volume in the "Volumes" page.  Ensure that the disk has been properly unmounted from the virtual machine before doing so.  You cannot detach a root disk. 

Voldetach

Note: If you are detaching a volume from a running instance, you should umount the volume from within the OS before you detach it.  Also, references to the volume to be detached should be removed from fstab to prevent errors upon reboot.

Note: Once a volume has been detached, it can be attached to any other VM in that zone. This can prove handy in some circumstances.

Snapshooting volumes

You can take a snapshot of a volume from the "Volumes" page by clicking on the Camerabutton button for that volume. 

Createsnap04

For more details about snapshots, go HERE 

Deleting volumes

You can delete a volume that is currently not attached to a virtual machine by clicking on the Terminatebutton button from the "Volumes" page. 

Delvol

Snapshots are a quick and easy way to protect your valuable assets. The rule of thumb is, when in doubt, take a snapshot. Even if you are making a "minor" change to your system, a snapshot could prove to be a life saver should something go wrong.

When you delete a volume, it cannot be restored. It is permanently destroyed. Be very cautious when doing this.