At some point, usually after you inventory what you have, estimate your requirements for continuity activities and resources. This exercise aids in assigning a value to the modifications in the current storage configuration installed, the additional redundant configurations you need, and other additional resources set for implementation in the event of trouble.
How much of the production configuration needs to be replicated within what time period will be evident from your continuity analysis. In estimating the level of redundancy, it is necessary to understand the relationship to the minimum data capacity required, the number of users, and the level of access. For example, if you plan for full redundancy, then the data capacity, number of users, and access are simply duplicated in an adjacent configuration. However, this is rarely afforded given the cost, and therefore requires a level of adjustment that takes into account the type of outage , and the level of business operation required for a particular time period.
For example, for unscheduled outages, the level of operation must be maintained for deposit transactions, with the related data available. However, the other transactions may be down for a period of no more than 15 minutes for a single processing cycle. Therefore, configurations have to reflect a level of redundancy to maintain the deposit suspense transactional data while the other transaction data, customer service, and portfolio services should have fault tolerant systems with a mean time to repair of 15 minutes per 12 hours.
In calculating these requirements, you must not only account for new configurations (there to meet necessary service levels), but also those modifications-reflected in existing production configurations-that accommodate redundant systems. In terms of NAS, this may be the addition of a redundant NAS device that mirrors the data. Within the more complex SAN configurations, requirements include: upgrades to switches to add expansion ports, E_Ports, software to enable interswitch linking, trunking, and redundant switch configuration and related devices.
One of the most challenging activities within this exercise is the inclusion of additional hardware and software components you didn't think about initially in contemplating storage configurations. These expenses include additional software licenses, upgrades to existing software, and the cost of new devices such as adapters and redundant servers.