This document relates the maximum number of devices allowed in a Backup Exec environment.  However, this does not mean that the maximum number of devices can be connected and then run simultaneously without performance impacts.  The primary purpose of this document is to address Deduplication/OST environments where the use of Remote Agents with Deduplication can quickly increase the internal number of devices that Backup Exec needs to track.

Backup Exec 2010 R3 has the following limits in regards to the support of unique devices.

• Backup Exec 2010 R3 Media Server: 256 devices per provider. Providers are SCSI, NDMP, OST.
• Backup Exec 2010 R3 Remote Agent for Deduplication (RAD): 256 configured devices per RAD
• Backup Exec 2010 R3: NDMP Server limit: 64
  • NDMP Servers include  RADs, NDMP servers (EMC/NetApp), and Remote Media Agent for Linux servers (RMAL)
• Backup Exec 2010 R3: Total Device Path Count cannot exceed 2048.

Example Configuration -

• Backup Exec 2010 R3 Media Server Target Devices:

Tape Library with 8 drives

• Remote Agent for Deduplication (RAD):

16 servers

• OST device configured with one (2) Logical Storage Units (LSU), and eight (8) concurrent operations each.

Note: Each LSU has a value of one device. Each concurrent operation configured has a value of one device.

1. Calculate the total number of devices on the media server.  1 Tape Library Changer + 8 Tape Drives + 1 Changer + 8 concurrencies for the first LSU + 1 Changer + 8 concurrencies for the second LSU = 27.

2. Calculate the total number of device paths at each RAD. 1 Changer + 8 concurrencies for the first LSU + 1 Changer + 8 device paths for the second LSU = 18.

3. The total number of device paths for this media server is then 27 (from step 1) + 16 (the number of RADs) * 18 (the number of devices each RAD has access to) = 27 + (16 * 18) = 315

In this example, there are 16 RADs configured. It assumes that all the RADs have access to the both LSUs on the OST device. With this said, the number of device paths from the Remote Agent for Deduplication is multiplied by the device count.

As the total number of NDMP Servers (RADs) is less than 64, the total number of devices per RAD is less than 256, and the total number devices for the media server is less than 2048, then the configuration is within the defined device count limits of Backup Exec 2010 R3.

This example does not cover all cases but provides generalized information on how to define and calculate the number of devices for a given media server.

 Note: An alternative to manual calculation is available at the URL below:

www.symantec.com/docs/TECH205843