Good post on availabity in the virtual world:
Long established techniques addressing application resilience, data availability and disaster recovery are being challenged by server virtualization technologies from companies such as VMware, Citrix and Microsoft. Where do we go from here?
…Who’s selling what? So who are the market players? The virtualization infrastructure vendors – VMware, Microsoft and Citrix Systems in particular – continue to build functionality to increase availability into their core products, threatening in some cases to squeeze out competition from third-party vendors. A core part of what they offer is the live migration of virtual machines, which can move workloads to a different server while they are running. This has the potential to eliminate the need for planned downtime altogether.But there is still plenty of room for other vendors to operate.
They range from storage array vendors with their own hardware-specific tools (such as EMC, Hewlett-Packard and NetApp) to software-based replication vendors (such as Double-Take Software and NeverFail).The storage vendors typically provide the best performance, but require an investment in expensive networked storage resources. Modular, iSCSI-based storage systems such as HP’s LeftHand and Dell’s EqualLogic are capitalizing on the new demand for availability, attracting customers that have previously been frightened away from shared storage by the complexities and expense of classic fiber channel-based storage networks. A related approach is that of the storage virtualizers, such as DataCore Software…