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GridStor® (Alternate Data Paths) - Examples

Table of Contents

Configuring Alternate Data Paths for Subclients

The following examples illustrate how to use the subclient data paths to effectively reduce media usage.

Example 1

In this example, a set of clients point to Storage Policy 1 while another set of clients points to Storage Policy 2. Each of these storage policies are configured with the default and alternate data paths using two MediaAgents to ensure that backup operations succeed when a component in the default path is not available. However, media consumption will be high since, by default, each storage policy writes to a media. (Storage Policies cannot be configured to share the same media.) In the sample diagram shown below, all client data routed through Storage Policy 1 use MediaAgent1, and all of the data that is routed through Storage Policy 2 use MediaAgent2.

Further, when a failover occurs, additional media are used by the new data path. This can be overcome by defining subclient data paths. To ensure that all backup operations use the same media, you can create one storage policy with both of the data paths that are configured. This storage policy is, in turn, used by all the clients. However, within their subclients, MediaAgent 1 is set as the default data path and MediaAgent 2 as the alternate data path for the first set of clients, and vice-versa in the second set of clients. In this case, it is not necessary to share the index because the MediaAgents and the libraries are connected in the SAN.

Example 2

In this example, client group 1 has a set of clients that use MediaAgent 1 and MediaAgent 2, while client group 2 has another set of clients that use MediaAgent 3 and MediaAgent 4. Both of these clients groups with their appropriate MediaAgents are separated by a firewall. As with example 1, media usage will be more if two storage policies are defined to accommodate this setup.

As illustrated in the sample diagram, the solution is to define one storage policy with four data paths that use each of the available MediaAgents. In addition, all of the clients in client group 1 can be configured with subclient data paths that point to MediaAgent 1 and MediaAgent 2, and all the clients in client group 2 can be configured with subclient data paths that point to MediaAgent 3 and MediaAgent 4. This will ensure both failover protection as well as minimal media usage.

Configuring Alternate Data Paths for Secondary Copies

The following examples illustrate how to use the secondary copies with data paths to perform Auxiliary Copies.

Example 1

In this example, the MediaAgents perform LAN-free operations that use a disk library for the primary copy and a tape library for the secondary copies.

The primary copy is created by backing up data to a local disk using the following data paths in the primary copy:

  • Default Data Path: MediaAgent 1, Disk Library 1
  • Alternate Data Paths: MediaAgent 2, Disk Library 2; MediaAgent 3, Disk Library 3

The MediaAgents are connected to a library (Library 1) in the SAN environment, and Auxiliary copies to tape are created using the following data paths in the secondary copies:

  • Default Data Path: MediaAgent 1, Library 1, Drive Pool 1 and Scratch Pool 1
  • Alternate Data Paths: MediaAgent 2, Library 1, Drive Pool 2 and Scratch Pool 2; MediaAgent 3, Library 1, Drive Pool 3 and Scratch Pool 3

Make sure that the Use Preferred Datapath option is enabled so that the system performs LAN-free operations automatically wherever possible.

Example 2

In this example, the MediaAgents perform LAN-free operations using a tape library to create both the primary and secondary copies.

For MediaAgents 1 and 2:

The primary copy is created with the following data paths:

  • Default Data Path: MediaAgent 1, Library 1, Drive Pool 1 and Scratch Pool 1
  • Alternate Data Paths: MediaAgent 2, Library 1, Drive Pool 2 and Scratch Pool 2

The secondary copy is created with the following data paths:

  • Default Data Path: MediaAgent 3, Library 1, Drive Pool 3 and Scratch Pool 3
  • Alternate Data Paths: MediaAgent 4, Library 1, Drive Pool 4 and Scratch Pool 4

For MediaAgents 3 and 4:

The primary copy is created with the following data paths:

  • Default Data Path: MediaAgent 3, Library 1, Drive Pool 3 and Scratch Pool 3
  • Alternate Data Paths: MediaAgent 4, Library 1, Drive Pool 4 and Scratch Pool 4

The secondary copy is created with the following data paths:

  • Default Data Path: MediaAgent 1, Library 1, Drive Pool 1 and Scratch Pool 1
  • Alternate Data Paths: MediaAgent 2, Library 1, Drive Pool 2 and Scratch Pool 2

Make sure that the Use Preferred Datapath option is enabled so that the system performs LAN-free operations automatically wherever possible.

Configuring Alternate Data Paths Using Windows MediaAgents That Are Connected to SAN Volumes

Assume you have two MediaAgents and one LUN volume configured as follows:

  • MediaAgent 1 has the volume mounted using iSCSI protocol, which allows the MediaAgent to access the LUN as local disk.
  • LUN volume is shared to allow MediaAgent 2 access to the volume using UNC paths.

To configure alternate data paths on these MediaAgents, perform the following configurations:

Configure a Shared Disk Library

  1. Configure a Shared Disk Library using MediaAgent 1 and MediaAgent 2.
    • MediaAgent 1 should access the disk library through the local path.
    • MediaAgent 2 should access the disk library using the UNC path.

Make sure there is connectivity between the two MediaAgents

  1. If  failover occurs because that data path is not accessible by MediaAgent1, then the index is copied directly from MediaAgent1 to MediaAgent2 for the job to be resumed.

Configure Data Path on a Storage Policy

  1. Create a storage policy and configure it to use the library from MediaAgent 1.
  2. For a storage policy copy, add the library from MediaAgent 2 as Data Path. Refer to the Add a Data Path to a Storage Policy Copy procedure to perform this operation.