In our recent webinar, “Flexible HA and DR for Virtual Server and Cloud Environments”, a majority of attendees indicated that replication was their sole method of providing high availability and protecting from disaster. While copying data to a secondary storage system or secondary data center is a critical first step in a DR or HA strategy, it’s not the complete solution. For rapid recovery, especially under duress, more is needed.
The copying of data from point A to point B is the job of replication and it can come from a variety of sources. Applications often provide a data replication facility, as do storage systems, and there are a plethora of software based replication solutions as well. But again, while having data in point B is a good start, it is not the total solution.
What is Replication Missing for Disaster Recovery?
Replication fails to provide a number of capabilities needed for real disaster recovery, especially for applications. First, disasters can come in various forms: an application can crash, its data can get corrupted, the server that’s hosting it can fail, and of course, the data center can suffer an outage. The problem with replication alone is that it really only protects from a storage system or data center outage. If the application server itself fails, or the software on that server freezes, then replication alone won’t help.
There needs to be a second instance of that server and its application available. This kind of HA solution used to require a cluster, which is expensive to buy and complex to operate. Now, thanks to virtualization and/or the cloud, providing that second server is relatively easy. What’s needed is intelligence to connect a replication process with the application.
The missing link is software that can monitor the application and its processes to make sure everything is operating and performing at the expected service levels. This software can trigger replication from anything to anything, meaning the destination can be another array in the data center or an array in a remote location – or even in the cloud. In our webinar “Flexible HA and DR for Virtual Server and Cloud Environments” we go through these requirements in detail to help you determine how to make your disaster recovery more intelligent.