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- June 27, 2014
- by David Lohnes
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In this installment of our continuing series on SharePoint disaster recovery planning, we will consider Microsoft’s third DR option: Hot Standby.
Microsoft describes a Hot Standby DR procedure as follows: “In a hot standby disaster recovery scenario, you set up a failover farm in the standby data center so that it can assume production operations almost immediately after the primary farm goes offline.”
With the Hot Standby model, the idea is that you have two SharePoint farms with two separate configuration databases that are continually kept in perfect synchronization by an outside-of-Microsoft replication process. In the event of a farm disaster, you simply redirect traffic to the secondary farm, and you’re back in business almost immediately.
The key to this recovery option is the abovementioned “outside-of-Microsoft replication process.” Microsoft does not provide any out-of-the-box methods for keeping two SharePoint farms in sync as required by this recovery model. Manual synchronization (replicating every single configuration change, patch, solution upgrade, etc. between the two farms by hand) is theoretically possible, but would place a high burden on the SharePoint administration and development teams, and would leave open the distinct possibility of human error introducing inconsistencies into the system—inconsistencies that would be very difficult to notice, track, or troubleshoot.
For this reason, most SharePoint teams that rely on a hot standby failover farm also rely on a third-party synchronization tool to automatically keep the two farms continuously in sync. Such tools greatly simplify the process of maintaining a standby farm and greatly reduce the possibility of human error while maintaining the synchronization. The downside is that these tools (such as AvePoint’s SharePoint High Availability and Metalogix’s Replicator) are usually quite expensive; in addition the organization must bear the cost of a second set of SharePoint and per-server third party licenses. Still, as in most things, you get what you pay for. For organizations that can bear the cost, Hot Standby is the gold standard SharePoint DR option.
- Easily the fastest recovery method
- The easiest recovery method to activate
- Probably the most reliable recovery method
- Offers the highest “fail back” potential. Once the original farm is back online and resynchronized, failback can be done on the fly.
- With the proper third-party tools, requires the least day-to-day maintenance to the DR plan. Simply set up the third-party replicator and let it keep everything in sync.
- Without third-party tools, has a very high administrative burden to maintain failover readiness. Indeed, the burden of manually keeping two farms in sync is almost certainly not bearable practically speaking.
- Can be very expensive to support the costs of duplicate farm infrastructure, replication tool, and duplicate licenses