Calculating the file hash
In the backup policy, enable the option and then enable the option to calculate the SHA-256 of the files. After SHA-256 is calculated, the file hash information is saved to the NetBackup catalog. The file hash information is then copied to the file hash server if the file hash server is configured.
The NetBackup catalog is expected to increase by 20% or more. You can configure to delete the file hash information automatically from the NetBackup catalog after it is copied to the file hash server. Add the line AUTO_CLEAN_FILE_HASH_FROM_CATALOG = 1 in the bp.conf file on the primary server.
You can calculate the file hash for the following policy types:
Windows
Standard
NAS-Data-Protection
Note:
This feature may affect the backup performance depending on the client configuration such as CPU and memory. If the CPU has SHA extensions, the hash calculation is faster than the CPU without SHA extensions.
To enable calculating the file hash
- On the left, click Protection > Policies and then click Add to add a new policy or select the existing policy to edit it.
- On the Attributes tab, select Use Accelerator and then select Calculate file hash.
After you enable this feature, the next backup is a full backup. It treats all data as changed data because it calculates the file hash for each file. The subsequent backups calculate the file hash for changed files only.
- Click Create or Save.