Cyclic Redundancy Check (CRC) Validation

The Cyclic Redundancy Check (CRC) validation verifies the integrity of the data secured by the backup operations and transferred over a network, and the data stored on the media. This data integrity validation is enabled by default.

CRC validation is done on the following:

  • When the data from clients travel over a network to a MediaAgent
  • When the data is written by a MediaAgent to a secondary storage media

Note: The data integrity validation can use up to 64 KB as the block size and depends on the data buffer size sent from the client to the MediaAgent.

How It Works?

For Write Operations

When a backup is run, the CRC validation works over the network and on the media in the following manner:

  • The client generates a CRC from the data that is backed up.
  • The data is sent over the network to the MediaAgent.
  • Another CRC is generated on the MediaAgent based on the data received.
  • The CRC generated from the client and the CRC generated on the MediaAgent are compared.
  • In case, there is a mismatch, it is indicative of network corruption and the data is sent again on the network.
  • After successful validation, the CRC is written on the media as part of the backup.

For Read Operations

During read operations like restores, data verification and auxiliary copy etc. the CRC validation works in the following manner:

  • Source MediaAgent reads the data available on the media.
  • The read operation generates a CRC which is compared against the CRC that was saved during the backup.
  • In case, there is a mismatch, it is indicative of corruption.

Last modified: 3/13/2020 9:04:21 PM