About conditions for support of replicated NetBackup catalogs
A NetBackup environment that is set up for replication is supported in the same way as any other NetBackup server. If the replicated catalog volume fails and is unrecoverable within a reasonable amount of time, NetBackup support recommendations are the same as in the case of an unrecoverable disk failure of a non-replicated catalog. You should restore the catalog from the latest available catalog backup on the main primary server.
Note:
Data can be lost in any data replication solution. To protect the NetBackup catalog, you must not solely rely on the replication technology due to the risk of failure of the replication technology. Data on the main NetBackup server can get corrupted due to replication to the alternate hot standby NetBackup server. Therefore, you must frequently back up the NetBackup server catalogs.
Warning:
Replication can adversely affect the application performance. Since additional time is required to commit changes to the NetBackup catalog, it may affect the overall backup times. Use replication at your own risk. Cohesity shall have no liability for any replication failure based on your failure to properly install, configure, and monitor your replication solution.
The conditions of support for replication of NetBackup catalogs are as follows:
The replication technology that is employed must maintain a consistent and write-ordered copy of the data at all times.
The use of asynchronous replication technologies is allowed, if write-order fidelity can be maintained.
The use of scheduled replication technologies such as hourly snapshots is not supported.
The NetBackup primary server must reside on the same virtual server that is controlled as a single entity.
The primary and the alternate primary servers must be of similar type, specification, operating system, and use the same virtual host name.
The alternate primary server must not have any other NetBackup function, neither in the same domain as the main primary server, nor in another domain. For example, you cannot use the alternate primary server as a media server if it is not used as a primary server. You also cannot use it as a primary server for another NetBackup domain. Catalogs are replicated but cannot be merged.
Configure both the clustered and the non-clustered environments to use a virtual host name and IP address for the NetBackup primary server that is separate from the physical host names and IP addresses of the servers. Separate virtual host name and IP address let you control the active primary server node through DNS routing. It also prevents the primary and the alternate primary servers from being active in the domain at the same time. For clustered environments this requirement is met automatically by the cluster configuration. For non-clustered environments the virtual host name must be specified during installation.
Ensure that the main primary server and the alternate primary server use the same version of NetBackup and dependent component. Verify that the operating system, NetBackup binaries, EEBs, and configurations files that are not included in the paths are specified for replication.
Replication between clustered and non-clustered primary servers is not possible. Server pairs must be either clustered or non-clustered.
The NetBackup catalog mount point must be the same at both the main and the alternate sites.
Only the catalog data is replicated between servers and must all be co-located on a single volume or volume set for replication. For clustered primary servers the cluster common volume is replicated.
For non-clustered primary servers, for details of the paths that must be linked to a volume set for replication,
Ensure that the virtual name or DNS alias does not resolve to both the main and the alternate hosts at the same time.
Catalog replication does not remove the requirement for catalog backup. Regularly back up the NetBackup catalog from the main primary server to protect against accidental image expiration or other inconsistencies that are introduced in the catalog on the main site and replicated to the alternate site.
If catalogs are replicated between NetBackup domains (rather than to a secondary server that can access the primary domain's media servers) only the backups that are written to the tape and the replicated BasicDisk storage can be restored in the disaster recovery domain.
Replication of the catalogs to an alternate primary server lets you restore data during a short-term outage of the main primary server. In cross domain replication configurations, ensure that backups can be run after a failover. The catalogs should be able to be failed back to the primary server at a later date without data loss. Consider this support condition when you plan making backups at the DR site during a prolonged outage and then moving back to the main site without losing information about the backups that are created at the DR site.
Verify if NetBackup comes up using the replicated copy on the alternate site. This usage is not a requirement for support.
Both the catalog and the backup images must be accessible at the alternate site.
Users need to address the procedures that are related to availability of valid copies of the backup images. Users should also define procedures for enabling the NetBackup server to restore from the images at the alternate site. This document does not address these procedures.
Users are responsible for installing, configuring, and monitoring their data replication solution. Users must ensure that the replication technology continuously maintains a consistent write-ordered copy of the NetBackup catalog volume.
Microsoft Distributed File System Replication (DFSR) technology is not supported as it does not guarantee write-ordered consistency of the files being replicated.
For more information, see https://support.cohesity.com/s/article/article-100043283