by Yaniv Valik
SR DR Specialist, DR Assurance Team
In my last post I took a closer look at the problems created by Replication Inconsistenies. Here’s a detailed look at another very common gap, why it happens, and how it can impact your operations.
Gap: Missing Network Resources
Risk: Extended recovery time
How does it happen? This risk can generally be traced to a configuration mistake which occurs when DR is not considered during the configuration process. The source host is accessing network file systems (CIFS/NFS). The network file systems are stored on a production server/array/NAS device. The target DR server also accesses the network file systems from the same production server on the production site. During a DR test, the production file server is not brought offline and the test succeeds. During a real disaster the production server will not be available.
What is the impact? If the network file systems were not replicated to a DR site, data loss will result. If the systems are replicated, recovery time will be extended while the administrator locates corresponding file systems on the DR site and mounts them on the DR standby server. This assumes the organization has excellent site documentation. Without it, however, data loss will occur.
Why does the DR test miss this? When running the DR test for a specific business service or application, most companies do not shut down the entire production datacenter. The DR test will be successful because the other assets are accessible and responding. Therefore, the DR site will use the production system unknowingly.
If this is of interest to you, you check out some other typical gaps on our website: https://www.continuitysoftware.com/products/availabilityguard/