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Secondary Index Server (Indexing Version 1)

Overview

Secondary index server automatically creates a copy of an index onto another MediaAgent, called a secondary MediaAgent, which is usually physically separate from the MediaAgent on which the primary index was created. Having a copy of an index ensures that it remains available if the primary index gets erased during a cleanup operation. Each secondary index server can support multiple MediaAgents.

This feature is useful for setups that would otherwise rely on tape recalls when a primary index is no longer available (for example, it was aged off or otherwise deleted from the primary MediaAgent).

Requirements

Implementing secondary index server requires a MediaAgent, which in most cases will be a separate MediaAgent, to hold a copy of the primary index. The secondary MediaAgent should have sufficient storage space in its index cache directory to store indexes for all of the MediaAgents for which it serves as a secondary index server. If the secondary MediaAgent is also serving as a primary MediaAgent for clients of its own, it should have additional sufficient storage space to act as a MediaAgent.

Examples:

  • MediaAgents MA1 and MA2 perform backups for clients. Each MediaAgent index directory has 500 GB of storage space.
  • MediaAgent MA3 performs backups for clients, and requires 500 GB for its own indexes.
  • If MA3 is deployed as the secondary index server for MA1 and MA2, then MA3 should have 1.5 TB total space allocated to its index directory.

Configuration

Configuration Settings

Secondary index server is configured through two additional settings:

  • The first setting, bISSECONDARYINDEXSERVER, is added to the MediaAgent that hosts the copy of the index (that is, the secondary index server).
  • The second setting, sSECONDARYINDEXSERVERNAME, which is added to the primary index server MediaAgent, identifies the secondary index server MediaAgent.

These two additional settings use the following parameters:

Setting Name

Platform

Description

Category

Type

Value

bISSECONDARYINDEXSERVER

Secondary MediaAgent

Makes the MediaAgent a Secondary Index Server.

MediaAgent

INTEGER

1

sSECONDARYINDEXSERVERNAME

Primary MediaAgent

The name of the secondary MediaAgent to which each index is copied after being created on the primary MediaAgent.

MediaAgent

STRING

The hostname of the secondary MediaAgent

Procedure

  1. Add the first setting, bISSECONDARYINDEXSERVER, to the secondary index server MediaAgent by following the steps described in Adding or Modifying Additional Settings from the CommCell Console.
  2. Add the second setting, sSECONDARYINDEXSERVERNAME, to the primary index server MediaAgent by following the steps described in Adding or Modifying Additional Settings from the CommCell Console.
  3. On the primary index server MediaAgent, restart the Commvault Media Mount Manager service.

Additional Information

Secondary Index Server Operational Information

  • During a backup job, an index is created on the primary index server MediaAgent. This MediaAgent copies the completed index to the secondary index server MediaAgent every 30 minutes in the background.
  • An index restore operation automatically copies the restored index to the secondary MediaAgent.
  • During browse, find, or restore operations, if the required index is not present on the primary MediaAgent, the copy of the index is automatically downloaded from the secondary index server.
  • Indexes present on the primary MediaAgent at the time that the secondary index server feature is enabled are not uploaded to the secondary index server. Jobs that are run after the secondary index server feature is enabled will upload their indexes to the secondary index server.
  • If the client name of the secondary index server MediaAgent is changed (via the Client Properties dialog box for the secondary MediaAgent), the sSECONDARYINDEXSERVERNAME additional setting on each primary MediaAgent that uses that secondary MediaAgent must be updated with the new name, and the MediaAgent Services on those primary MediaAgents must be restarted.

Secondary Index Retention and Cleanup

Index copies are saved in the CatalogServer folder, which is in the index cache directory. To ensure availability, the secondary copy of an index is subject to the following retention rules:

  • Secondary indexes are not subject to event-based cleanup operations, but scheduled cleanups are performed on them. Aging for each index is determined by the retention rules set on the secondary MediaAgent. See Index Directory Cleanup.
  • Setting a longer retention time on the secondary MediaAgent ensures that secondary indexes are retained longer than primary indexes.

FAQs

Does a backup job fail if the MediaAgent cannot access the secondary index server?

No, the backup does not fail. The index is copied to the secondary index server when the secondary MediaAgent becomes available again.

Can a MediaAgent use itself as a secondary index server?

Yes, but this removes some of the advantage of having a secondary copy. For example, the MediaAgent host computer may experience a hardware failure. If both copies of the index are on that one computer, both copies may be temporarily unavailable or even permanently lost. Also, having the index copied to a separate MediaAgent means that it is subject to a different (normally longer) retention policy, giving more opportunity for recovery if needed.

Can the primary and secondary MediaAgents be hosted on different operating systems?

Yes. For example, a primary MediaAgent can be hosted on a Windows computer while its designated secondary MediaAgent is hosted on a UNIX computer.

Last modified: 5/8/2018 2:14:31 PM