- VASA Provider 9.6
- AppDM Application Data Management
ONTAP has supported Application Data Management (AppDM) for provisioning application storage objects like FlexVol volumes, which uses balanced placement to place the objects on aggregates with the best space and performance capacity, and assigns a QoS policy. AppDM provisioning was supported for vSphere Virtual Volume (vVol) objects using AppDM APIs starting in ONTAP 9.4 together with ONTAP VASA Provider 7.2.
While there are benefits with AppDM, we have also seen some issues. These include:
- impacts on performance with > 100 concurrent vVol operations (create, delete)
- vVol naming issues, which also impacts vSphere HA (BURT 1212933)
- vVol creation/migration problems due to changes VMware made in vCenter 6.7U2 (BURTs 1245583, 1262822, 1262631)
Given these issues, NetApp Engineering and Support recommend that AppDM be disabled. We have released VASA Provider 9.6P1 where this is disabled by default. This KB provides information on the requirements for disabling and the impact of doing so. The best approach is to migrate or delete any existing AppDM vVols, update any Storage Capability Profiles that include Adaptive QoS or "Performance service level", and then upgrade to 9.6P1. This KB also includes the steps to manually disable AppDM should it not be feasible to upgrade. The option to disable AppDM is not supported in VASA Provider 7.2.X releases.
Requirements for disabling AppDM
NetApp does not recommend the use of a vVol datastore with a mix of AppDM and non-AppDM vVols. Therefore, before disabling AppDM any existing AppDM vVols in any vVol datastore managed by the VASA Provider should be migrated to another non-AppDM (e.g., non-vVol such as traditional or local) datastore or deleted. AppDM vVols are created by default with ONTAP 9.4 or later releases together with either VASA Provider 7.2, 7.2.1, or 9.6.
Once all AppDM vVols have been migrated to another non-AppDM datastore, AppDM may be disabled as described below. You will also need to update any Storage Capability Profiles that include Adaptive QoS or "Performance service level", either setting Performance to None or changing to a QoS policy with Max and/or Min QoS as needed.
After AppDM has been disabled, vVol VMs may be migrated back to the vVol datastore, or the datastore itself may be destroyed if no longer needed.
Impact of disabling AppDM
AppDM enabled vVol support for performance service levels (Adaptive QoS) and balanced placement. However, the defined service levels that are available (Value, Performance, Extreme) are better suited for multi-TB objects like FlexVol volumes, and for many vVols the absolute minimum service level would be used. Using Max and/or Min IOPS (throughput ceiling and floors) is a better approach for vVol sized objects, and this is supported without AppDM. Also, AppDM would use a performance service level of Value when the SCP specified performance value "None" which can impact performance, whereas non-AppDM VVols use an infinite limit when "None" is specified.
Balanced placement is also useful for large ONTAP clusters where FlexVol volumes are spread across nodes with different workloads and performance capabilities. But many customers use only one or two ONTAP nodes for a vVol datastore, where balanced placement is less useful. NetApp is looking at approaches to support balanced placement when placing FlexVol volumes for a VVol datastore across cluster nodes and aggregates.
For non-AppDM vVols, changes to VM policy/SCP can cause the VASA Provider to migrate the vVol from one FlexVol volume to another in the datastore (for example, from an encrypted to unencrypted volume). AppDM vVols can support changes to performance level but does not support automatic migration on policy change. So, this is a benefit of disabling AppDM. AppDM also only supported a maximum of 10 FlexVol volumes within a single vVol datastore.