1. A computer program product for maintaining a multiple-site configuration for continuous availability over long distances, the computer program product comprising one or more non-transitory computer-readable storage media having stored thereon: first program instructions executable by a first processor located at a first computing site, the first program instructions being configured to execute a first instance that is designated as an active instance and associated with a priority workload; second program instructions executable by a second processor that is communicatively coupled to the first processor and located at a second computing site, the second program instructions being configured to execute a second instance of the priority workload that is designated as a standby instance; a first replication module configured to replicate a unit of work data associated with the priority workload being executed as the active instance at the first computing site to the standby instance at the second computing site, wherein the unit of work data comprises a computing transaction and transactional data that is logged in response to completion of the computing transaction; and a second replication module configured to replicate data stored in a first storage volume to a copy on a second storage volume, wherein the first storage volume is associated with the first computing site, and the second storage volume is associated with a third computing site that is communicatively coupled with the first computing site; and a workload availability module configured to: in response to the first computing site being unavailable: designate the second instance as the active instance; configure the third computing site to execute a third instance associated with the priority workload, and designate the third instance as the standby instance, wherein execution of the third instance is started from the copy on the second storage volume; and monitor a metric associated with the first computing site and determine the first computing site is unavailable based on the metric, wherein the first program instructions are further configured to restart the first instance associated with the priority workload based on the first computing site subsequently becoming available and subsequently designate the first instance as the active instance, and wherein the second computing site is separated from the first computing site by a first distance greater than a metropolitan area network.