PowerProtect Data Manager 19.15 Microsoft SQL Server User Guide

Configuring usage limits of DD resources

Use the PowerProtect Data Manager UI to configure capacity quotas and stream limits for the DD system storage units that are under the control of PowerProtect Data Manager. The PowerProtect Data Manager Administrator Guide provides more information about working with storage units.

For other storage units, use either the DDOS commands or the DD Administration UI to set limits on usage of the following DD resources:

• Capacity: The amount of hard drive capacity that the application agent uses on a DD host. Capacity limits are based on the used logical space, which depends on the amount of data that is written to a storage unit before deduplication. Logical capacity is the size of the uncompressed data. For example, when a 1 GB file is written twice to the same empty storage unit, the storage unit has a logical size of 2 GB, but a physical size of 1 GB.
• Streams: The number of DD Boost streams that the application agent uses to read data from a storage unit or write data to a storage unit on a DD host.
  NOTE:The Microsoft application agent supports usage limits on DD resources for Application Direct operations only.

The term quota collectively describes the capacity soft and hard limits of a storage unit. Stream limits are called limits.

Both capacity and stream usage support soft and hard limits:

• When the Microsoft application agent exceeds a soft limit, the DD host generates an alert. If the administrator has configured a tenant-unit notification list, the DD host sends an email to each address in the list. The Microsoft application agent can continue to use more of the limited resource after a soft limit is exceeded.
• When the Microsoft application agent exceeds a hard limit, it cannot use any more of the limited resource.

The administrator must create (or ask to have created) a separate storage unit for each application agent host or set of hosts that are limited.

For example, if there are 10 application agent hosts, the administrator must create at least 10 storage units to limit the storage unit capacity that each application agent host uses. To use fewer storage units, the administrator must group the application agent hosts and assign the group to a single storage unit. The application agent hosts in the group share this storage unit. However, you cannot limit the consumption of a storage unit by each host. One application agent host can consume 100% of the storage unit. The resources are consumed on the first-come, first-serve basis.

To determine the stream limits of a storage unit, run the following command:

msagentadmin.exe administration --listSU --config <full_path_to_the_configuration_file> [--debug 9]

Example output of the command:

active write streams: 11
active read streams: 0
soft limit write streams: none
soft limit read streams: none
soft limit combined streams: 40
hard limit combined streams: 60