Expanding a disk in the cloud

Expanding a disk takes place in two stages:
  • The actual increase of the volume of the disk connected to the instance;
  • Expansion of the size of the partition from within the OS.

This section describes the steps necessary for changing the size of a disk connected to an instance (first stage). The subsequent steps are described in our documentation.

Increasing the size of a system disk

Note

The system disk is the disk from which the instance is created and launched.

  1. Correctly terminate all instance OS processes.
  2. Shut down the instance.
  3. Delete the instance. Before deleting it, be sure to check that the boot disk will not be deleted by the deletion of the instance. This check can be performed via the openstack cli management interface. The option itself is created at the point that the instance is created. (By default, the option ‘Delete disk when instance is deleted’ is disabled)
  4. Expand the disk via the web interface using the SIM-Cloud dashboard (using the ‘Expand disk’ item of the pop-up menu for the disk required).
  5. Create an instance from the now-expanded disk.
  6. Perform disk expansion within the OS.
  7. Complete configuration of network and connect additional disks (where necessary).

Increasing the size of an additional disk

  1. Before disconnecting the disk, check that the disk is not being used by the system or by applications, i.e. that the disk is not required for read or write operations. If the disk is in use it can not be disconnected (to prevent the potential loss of data that could occur during the period of arbitrary disconnection). We also recommend that you disconnect the disk using the operating system beforehand and then disconnect it using the management interface dashboard. If the process of defining the source of use of the disk is difficult, you can perform a shutdown of the instance with a subsequent disconnection of the disk.

Note

We have carried out a large number of tests on various configurations; these tests have consisted of connecting additional disks and also removing them. Our results have shown that the disk cannot be disconnected if it is engaged in read/write operations. If the disk is being used, no disconnection from the instance can be performed; the disk changes to the ‘detaching’ status and remains in this state. After this, intervention by the SIM-Cloud administrator may be necessary. When the disk being disconnected stops its r/w actions it continues in the ‘detaching’ status for a period of time, after which it detaches and enters the ‘available’ status.

  1. Expand the disk via the web interface using the SIM-Cloud dashboard (using the ‘Expand disk’ item of the pop-up menu for the disk required).
  2. Connect the disk to the instance.
  3. Start the instance.
  4. Perform disk expansion within the OS.