One of the best things to come out of VMworld 2011 was the announcement of the latest version of VMware's vCenter SRM (Site Recovery Manager). While previous iterations of SRM have brought little more than bug fixes and relatively minor feature additions, SRM 5.0 packs in a number of critically important features.
Those features, including built-in host-based replication and automated failback support, substantially increase the capabilities of SRM -- even in small to midsize business environments where it had previously gained little interest due to its relatively high cost of implementation. The introduction of replication to SRM 5.0 is also a continuing reminder of VMware's transformation into a de facto storage company as it tacks more and more storage array functionality into its product line.
SRM before 5.0
At its heart, Site Recovery Manager was and still is a site failover automation engine. Prior to SRM 5.0, there was nothing that SRM did for you that you couldn't do by yourself manually. However, that's certainly not to say that it was without any value -- far from it. By automating the site failover process, you could shave hours or even days off of the time that it would take to reconstitute a virtual infrastructure at a warm site.