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. 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. They come in several flavours: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 150 300 IOPS, which corresponds to a fast 10K 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 300 600 IOPS.
• VeryFast: Delivering 1K 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

Most of our volume-types 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 "SSD-1K" flavor we can use the following command:

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

Revoke access to volume-types

To revoke the access given for a specifiv volume-type the following command can be used:

$ openstack volume type unset --project DEMO_guide SSD-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:

eigil@manager:~$$ openstack quota show default
+----------------------+---------+
| Field                | Value   |
+----------------------+---------+
    ....
| volumes              | 10      |
| volumes_Fast         | 0       |
| volumes_Normal       | -1      |
| volumes_Slow  SSD-1K       | -1      |
| volumes_VeryFast     | 0       |  ....
+----------------------+---------+

Which means that we normally does not allow a tenant to create anything else than Normal and Slow volumes. To give the tenant "eigil" access to create a faster volume one would change this tenants quotaWhen 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 SSD-1K. In that case we can use the following command to limit the amount of SSD-1K volumes for the project DEMO_guide:

eigil@manager:~$$ openstack quota set eigilDEMO_guide --volumes 1 --volume-type FastSSD-1K

Resulting in changed quotas:

eigil@manager:~$ openstack quota show eigilDEMO_guide
+----------------------+----------------------------------+
| Field                | Value                            |
+----------------------+----------------------------------+
   ... 
| volumes              | 10                               |
| volumes_Fast  SSD-1K       | 1                                |
| volumes_Normal       | -1                               |
| volumes_Slow         | -1                               |
| volumes_VeryFast     | 0                                |  ...
+----------------------+----------------------------------+

...