Last month, we showed you what’s new in OpenStack Havana in a webinar that you can download here. We explained, among other things, what’s new in OpenStack Block Storage Service. (See the previous part of this summary here.) This time, we’ll talk about volume migration, transferring a volume from one tenant to another, and improved driver support.
One of the more interesting advancements in Havana as far as Cinder is concerned is the ability to migrate a volume. This is something only administrators can do, but it’s very useful because you can move a volume to another host or to an entirely different backend, like so:
Extend the size of an existing volume
Use Admin API to migrate a volume to a different Cinder back-end
For example, you might archive a volume that’s not being used from an SSD to something slower, or vice versa. This is a live migration. Users won’t even know that it’s happening. No reads or writes will be lost–they might just see a little performance blip while things are getting moved and operations are on hold. Please note that you can’t migrate a volume if it has snapshots.
Transfer a volume from one tenant/project to another
One feature that people have been seeking for a long time is the ability to share data between projects. While you still can’t actually share, one thing that you can do in Havana is transfer a volume from one tenant or project to another. While both projects can’t use it at the same time, at least you can move the data. You create a transfer from one tenant, and then accept it from the other, as shown below:
# Tenant A cinder transfer-accept # Tenant B
Another thing people are really excited about is the addition of Ceph to the mix. In Havana, you can use Ceph as either a volume or a backup target, and if you’re using it for both, Cinder will attempt to do a differential backup rather than a full backup, so you can store multiple versions, and a whole lot faster than doing a full backup.
All you need to do to make this available is to go ahead and enable this new driver in your configuration file:
The backup layer will now let you backup any iSCSI device, as long as it doesn’t have any internal optimizations. Also, there have been some improvements to the Windows Storage Server driver, as well as IBM’s Storwize and Tivoli Storage Manager drivers.
Havana also brings some improvements for the Huawei and Nexenta drivers, and new drivers for Dell EqualLogic and IBM General Parallel File System.
There have been a lot of improvements to VMware driver in Havana as well. A lot of those improvements involve your ability to manage OpenStack resources from within VMware vCenter. If you’re currently on VMware and you’re thinking about adding OpenStack, this is going to make it a lot easier for you. The VMware hypervisor now supports Cinder volumes, and there’s a new VMDK driver for Cinder, so you can manage your Cinder drives from within vCenter. You can also control your cloning strategy and decide whether to do full clones, where to copy the drives or linked clones, where the VMs share a drive, down to the instance level. You can also control multiple clusters from within vCenter, which is particularly beneficial if you have a large installation.
For further information
For a full look at what’s new in OpenStack Cinder and Glance, what the new components Heat and Ceilometer bring, and what’s going to be featured in the Icehouse release, please check out the slide decks below. You can also see the entire presentation, along with the explanatory audio and Q&A, here.