Media device selection (MDS) and resource allocation
Based on the global DTE mode, client DTE mode, media server DTE mode, and image DTE mode, the resources are allocated. For dynamic storage units, like MSDP or Storage Unit Group, a media server with the DTE mode On is preferred if that is a requirement for the job.
If the job demands a media server with the DTE mode On, but such a media server is not available, NetBackup falls back on the original resource allocation decisions.
In such cases, it is possible that the job goes ahead and sees a failure later on during job execution (in nbjm or bprd or other such daemons and CLIs), where NetBackup the DTE is required by media server.
The following process describes how the media device selection and DTE validations take place:
- In case of a backup operation, directly go to step 2. For any other operations such as restore, duplication, replication, import, verify, the source image DTE mode is taken into consideration:
If the DTE mode of an image is ON, the media server DTE media server is ON, irrespective of any other DTE configuration.
If DTE mode of a image is OFF, then check for global, client and media server DTE mode.
- If the global DTE setting is ENFORCED, then a DTE enabled media server is preferred.
- If the global DTE setting is PREFERRED ON or PREFERRED OFF, a client DTE mode is taken into consideration.
If the client DTE mode is ON - DTE enabled media server is preferred
If the client DTE mode is OFF - any available media server can be selected
If the client DTE mode is Automatic - the decision is made based on the global DTE setting. It means if the global DTE setting is set to PREFERRED OFF, select any available media server, else select the DTE enabled media server.
During resource allocation, many parameters play an important role. Following are the special conditions:
If the client name is blank, it signifies a secondary operation such as duplication, replication, import, verify and so on. The image DTE mode or global DTE mode are honored.
If the client name is not blank, however it is not present in the host database as the client is earlier than 8.0, the client does not support DTE. Hence, any media server can be selected.
After checking the global and client DTE settings, media server's version and its DTE setting are checked:
NetBackup 9.1 and later media servers are by default DTE capable and DTE enabled.
DTE_IGNORE_IMAGE_MODE setting (for any secondary operations based on an image)
If the image DTE mode is ON, and if the DTE_IGNORE_IMAGE_MODE option is applied, the global, client, and media server settings are used for the media server selection.