Shared volumes can be attached to multiple servers. They are typically used in cluster applications and allow any attached volume to access the data on a common volume.
PowerVC 1.2.3 managing PowerVM supports shared volumes, allowing you to use your volumes more effectively by attaching them to multiple virtual machines. With PowerVC, you can:
Mark the volume shareable or non-shareable
Share the boot or data volumes
PowerVC does not do any locking to prevent multiple hosts from writing to the volume. Its application responsibility.
How to make the volume shareable
You can make a volume shareable during or after volume creation. By default, volumes are not created as shareable. To make a volume sharable during creation, simply enable the checkbox
“Enable Sharing” After successful volume creation, on the volume properties “Sharing enabled” will
be set to True.
To change whether a volume is shareable after creation, view the volume details, then select “Edit Volume” You can change this setting at any time, for both boot and data volumes.
You can also use the volumes REST API multi-attach flag to enable or disable sharing. See “OpenStack Block storage (Cinder) APIs” in the Knowledge Center for details.
Attaching a shared volume
When you use PowerVC to attach a volume, the user interface will display all the available storage as well as the in-use shareable volumes, to allow additional attachment of shared volumes.
Note that when attaching a volume, you can specify whether the volume should have boot or data connectivity. If a volume is attached to multiple virtual machines, it must have the same
connectivity type on all of them. Therefore, you cannot change the Boot Set
attribute for a volume that is attached to another virtual machine.
Volume Attachment Details
To see which virtual machines are attached to a volume, open the volume’s details page. It will display the name of each attached virtual machines using the shared volume.
Deleting a Shared Volume
Before deleting a shared volume, you must detach the shared volume from all virtual machines.
- Shared volumes are only supported on PowerVC Standard managing PowerVM. Note – IBM i VMs do not support shared volumes.
- PowerVC does not control the volume access. The application is responsible for determining how to use each volume and providing access control. Some applications require concurrent access and some require failover access.
- The backing storage must support shared volume access.
PowerVC not only allows you to use your shared storage, but it also gives you a simple interface for managing shared storage volumes. This lets you spend more time running your business and less time worrying about your infrastructure. If you have comments or questions, I’d love to hear them – just post them below! And don’t forget to follow us on Twitter, LinkedIn, and Facebook!