SAS Disaster Recovery Policy for SAS® Viya® 3.4
Disaster-recovery planning is important for any critical business system, including production systems running SAS® Viya®. SAS customers should and usually do have disaster-recovery plans for their SAS® deployments, SAS applications, and SAS data files. Because the implementation of SAS Viya is often highly customized and each customer can have different requirements for replicating SAS content, there is no single tool or process that comprehensively meets all of the SAS disaster-recovery needs.
This position statement assumes that you are familiar with the concepts in the "Backup and Restore" section of SAS® Viya® 3.4 Administration.
Disaster recovery is not the same as high availability. Though both concepts are related to business continuity, high availability is about providing undisrupted continuity of operations whereas disaster recovery involves some amount of downtime, typically measured in days. This position statement addresses disaster recovery. SAS recommends that disaster recovery be predicated on regular, full system-image backups or system clones, and that disaster recovery processes be validated on a regular basis.
Use disk cloning or disk imaging of all disks to create and maintain a full-system backup or clone of the production operating environment. As necessary, supplement regularly scheduled disk cloning and imaging with scheduled file-system backups, third-party database backups, and other backup mechanisms that are supported by your operating-system vendor.
Note: Throughout this position statement, the word “clone” means an exact copy of, at a minimum, the following from the production system:
- The operating system
- The operating environment. For example: User Identifiers (UIDs) and Group Identifiers (GIDs), environment variables, mount points, kernel settings, Microsoft Windows registry, host names, IP addresses and so on
- All user home directories
- All third-party applications
- The SAS deployment (and all SAS configuration directories)
- SAS data files
- External data files (relational database management systems [RDBMSs] and data files from other software applications)
If the SAS production environment is virtual or container-enabled, you can maintain a full-system clone using a cloning process that is supported by your virtualization/container software provider. If the SAS production environment is on a bare-metal server, use a disk-cloning or system-imaging technology that is supported and accepted by the operating-system vendor.
Note: A copy of ONLY the SAS deployment is NOT considered a full-system clone.
A disaster-recovery plan for SAS environments needs to incorporate disaster-recovery procedures for the external systems and processes that SAS uses or depends on. These external systems and processes might be as simple as a DNS server address or more complex, such as another production application exchanging data with SAS processes. Additional considerations include:
- External customer data: Customer data is often located in databases or network-file systems that are external to the machines that host the SAS deployment. Because SAS does not provide tools to back up or restore such data, you must consider data backups as part of your disaster-recovery plan.
- External systems and processes: SAS deployments frequently interact with other systems and processes. Thus, a disaster-recovery plan for SAS environments needs to incorporate disaster-recovery procedures for the external systems and processes that SAS uses or depends on. These external systems and processes might be as simple as the use of a DNS server address or more complex such as another production application exchanging data with SAS processes. SAS does not provide tools to address such external systems and processes.