CommCell Disaster Recovery
CommCell disaster recovery is a set of procedures that are used to prepare for and recover from a CommCell disaster. A CommCell disaster can be defined as:
- Loss of CommServe functionality (CommServe host or services failure)
- Loss of access to storage resources (MediaAgent or library failure)
- Loss of a production service (client or application failure) resulting from lost or corrupted data.
Restoring functionality for your organization can mean replacing failed or old hardware, reinstalling software, renaming hosts, changing IP addresses (licensing), importing tapes, or restoring the CommCell database. Any disaster recovery scenario that you design involves restoring functionality of one or more of these components.
CommCell Disaster Recovery Types
Disaster Recovery (DR) types are defined by your organization’s Recovery Time Objectives (RTO) and Recovery Point Objectives (RPO). Achieving these objectives usually determines and depends on your degree of preparedness for disaster.
Disaster preparedness comes in many degrees. According to the Seven Tiers of Disaster Recovery, Tier 0 is defined as a no off-site data, with no requirements to back up data, while Tier 7 is defined as having a highly automated, business- integrated solution, managing a complete switch of all resources from one site to another automatically.
Regardless of which Disaster Recovery tier you implement for business continuity, recovering CommCell functionality requires the recovery of the following major components in the order listed:
- CommServe functionality
- MediaAgent functionality
- Access to protected storage (library/media)
- Client functionality
Depending on your CommCell environment and the scope of the recovery, you can complete steps 2, 3 and 4 in phases thus enabling you to recover priority clients while other MediaAgents, data, and client hosts are brought online. You can shorten recovery time by having computer hosts and software pre-configured as alternative or standby hosts for critical CommCell components.