Our volume service is hosted on the ceph cluster, and delivers add-on disks for the vm's. These volumes are all

Volume types

We provide variuos volume-types which differs in which disks they are places on, and which qos-settings are applied to them. The volumes are shaped performance-vise, to prevent single tenants from overloading our ceph cluster. They come in several flavours:. The flavors available differs a little between our platforms.

StackIT

In stackIT the storage consists of both SSD's and HDD's with a SSD-caching-layer. We place most cinder-volumes on HDD's, while the more demanding ones are placed on the SSD's. Be aware though that the SSD's only have ~35% of the storage-capacity of the cluster, and also carries all root-disks. The available cinder-types are:

• HDD-300: The default kind available to all tenants. Shaped to 300IOPS read/write, and is thus comparable to a fast 15k RPM HDD.
• HDD-600
• SSD-300
• SSD-1K
• SSD-4K
• SSD-8K

SkyHiGh

The SkyHiGh storage consists only of SSD's. Abput half of them are consumer-drives and half of them are enterprise-class SATA drives. The latter drives gives a lot more performance, and we are thus placing the root-disks of VM's on these. All cinder-volumes are placed on the Samsung EVO-drives. In SkyHiGh we provide the following cinder types:

• SSD-300
• SSD-600
• SSD-1K
• SSD-4K
• SSD-8K

Legacy types

Previously we had a set of cinder-types common for all our platforms, but these wont allow us to be as flexible in the placement of the data, and is thus deprecated. They are still present, but we would like to phase out all volumes of these types.

• Slow: The slow volumes are shaped to 50IOPS, which is rather slow. It can be used to simulate very slow disks for instance.
• Normal: This is the general purpose volume type. It is used by most tenants for their general purpose storage needs. It is shaped to 300 IOPS, which corresponds to a fast 15K RPM HDD.
• Fast: If a tenant needs more performance than the Normal type they can request a permission to create a "Fast" volume, which deliveres 600 IOPS.
• VeryFast: Delivering 1200 IOPS, the VeryFast volume can give a much greater performance than the other volume types. We should however be careful assigning this volume to our tenants, as it is capable to put some real load onto our ceph cluster if we have multiple of these volumes.

Give access to volume-types

The Most of our volume-types Fast and VeryFast are set as private volume-types, and we need to share these types with a project in case the project needs a volume of this type. If we want to give the project "DEMO_guide" access to volumes of the "FastSSD-1K" flavor we can use the following command:

$ openstack volume type set --project DEMO_guide FastSSD-1K

Revoke access to volume-types

...

$ openstack volume type setunset --project DEMO_guide FastSSD-1K

Quotas

tip : To see what quotas is changeable, use : openstack quota set --help

The default quotas for cinder volumes are limiting the amount of volumes a project can create, but it does not limit any of the volume-types:

$ openstack quota show default
+----------------------+---------+
| Field                | Value   |
+----------------------+---------+
    ....
| volumes              | 10      |
| volumes_Fast         | -1      |
| volumes_NormalSSD-1K        | -1      |
| volumes_Slow         | -1      |
| volumes_VeryFast     | -1      |  ....
+----------------------+---------+

When giving access to faster volume-types we should make sure to limit how may fast volumes can be created. For instance, we might want to allow a certain project create 10 volumes, but only one of the type FastSSD-1K. In that case we can use the following command to limit the amount of Fast SSD-1K volumes for the project DEMO_guide:

$ openstack quota set DEMO_guide --volumes 1 --volume-type FastSSD-1K

Resulting in changed quotas:

eigil@manager:~$ openstack quota show DEMO_guide
+----------------------+----------------------------------+
| Field                | Value                            |
+----------------------+----------------------------------+
   ... 
| volumes              | 10                               |
| volumes_FastSSD-1K         | 1                                |
| volumes_Normal       | -1                               |
| volumes_Slow         | -1                               |
| volumes_VeryFast     | -1                               |   ...
+----------------------+----------------------------------+

...