Data Protection Advisor - How to check and tune the DPA memory configuration after adding memory to the DPA servers

Data Protection Advisor (DPA) memory tuning is required if memory has been added to the DPA Application or Datastore servers. Memory tuning configures the DPA services/processes on the amount of server/system memory that it can utilize. 

The DPA Application is primarily a Java based application and the amount of memory it is tuned to is a soft memory limit. The application can use more than the configured limit in some situations, although normally not dramatically more memory.

The DPA Datastore is primarily a Postgres based application. The amount of memory it is tuned to is a hard limit, but this will not be easily visible using utilities such as Task Manager (Windows) or top (Linux). This is because Postgres generally uses shared memory.

When the DPA is installed, the memory is automatically tuned based on the total server memory.

Checking the current DPA memory configuration on the Application and Datastore servers

To check the new memory configuration on the Application server, view the configuration which is stored in the executive.log (example: <install dir>/emc/dpa/services/logs/executive.log). Start at the end of the file and search backwards for the following reference. The RAM configuration amount is seen after the -XmX reference, example:

Command[3] : -Xmx22937m

The value above is listed in megabytes (m) and equates to 22.9GB.

To check the new memory configuration on the Datastore server, run the following command:
<install_path>\emc\dpa\services\bin> dpa ds tune
 

[root@dpads01 bin]# ./dpa.sh ds tune

EMC Data Protection Advisor

[INFO] Current Datastore Service tuned expecting 16384MB of host memory

Command completed successfully.

Changing (tuning) the current memory configuration on the DPA Application and Datastore

When additional memory is needed for DPA and added to the server/system, DPA needs to be tuned so that it utilizes the memory that was added.

For example, say the memory on both of the DPA servers were initially 16GB and now the memory has been raised on both servers to 32GB. One would like DPA to utilize that additional memory.

On the DPA Application server the following command should be run to configure it for the new memory total.

Windows: <install dir>\emc\dpa\services\bin> dpa app tune 32GB
Linux: <install dir>/emc/dpa/services/bin> ./dpa.sh app tune 32GB

You will see output below. Example is from a Linux server:

[root@dpapp01 bin]# ./dpa.sh app tune 32GB

EMC Data Protection Advisor

Set Application service memory usage to 22937MB : Confirm [Y|N]
y
Application service successfully tuned.

Command completed successfully.

Per the Administration Guide:
DPA automatically configures itself to use a portion of the memory amount specified in the command.

The DPA tune command on the DPA Application will tune the application to approximately 70% of the specified memory amount. This is in part due to the behavior of Java mentioned previously, where the memory configuration is a soft limit. This provides a buffer for Java to exceed the soft limit.

Note: In some circumstances, the DPA Application can be tuned to use more than than the 70%, but care should be taken with doing this. Please consult with Dell Technical Support for guidance.

On the DPA Datastore server the following command should be run to configure for the new memory total.

Windows: <install dir>\emc\dpa\services\bin> dpa ds tune 32GB
Linux: <install dir>/emc/dpa/services/bin> ./dpa.sh ds tune 32GB

You will see output below. Example is from a Linux server:

[root@dpads01 bin]# ./dpa.sh ds tune 32GB

EMC Data Protection Advisor

Set Datastore service memory usage to 32768MB : Confirm [Y|N]
y

Datastore Service successfully tuned.

The new memory utilisation for the datastore will not
take effect until the datastore service is restarted.


Command completed successfully.

The DPA tune command on the DPA Datastore will tune it to 100% of the specified memory amount. This is normal and expected. As mentioned earlier on in this KB article, Postgres utilizes "shared memory", so this configuration is correct and will not cause any issues with operating system memory resource consumption or need.

In the case of both the DPA Application and Datastore, the DPA services will need to be restarted for the tuning command to take effect:

The recommended restart sequence is as follows:
 - Stop the Application server:  Linux: ./dpa.sh svc stop / Windows:  dpa svc stop (or from services.msc)
 - Stop the Datastore server:  Linux: /dpa.sh svc stop / Windows: dpa svc stop (or from services.msc)
 - Start the Datstore server: Linux: ./dpa.sh svc stop / Windows: dpa svc stop (or from services.msc)
 - Start the Application server: Linux: ./dpa.sh svc start / Windows: dpa svc start (or from services.msc)

The newly tuned memory configuration for the DPA Application and Datastore can be verified as previously mentioned in this KB article.

Please contact Dell Technical Support for further details or information.