As opposed to public cloud computing paradigms, which are generally deployed as web servers or development systems, private cloud computing systems are preferred by mid and large size enterprises because they meet the security and compliance requirements of these larger organizations and their customers.
Private cloud hosting offers a number of significant advantages – including lower costs, faster server deployments, and higher levels of resiliency. What is often over looked is how the Private Cloud can dramatically changes the game for IT disaster recovery in terms of significantly lower costs, faster recovery times, and enhanced testability.
As opposed to public cloud computing paradigms, which are generally deployed as web servers or development systems, private cloud computing systems are preferred by mid and large size enterprises because they meet the security and compliance requirements of these larger organizations and their customers.
When production applications are loaded and running on a private cloud, they enjoy a couple of key attributes which dramatically redefine the approach to disaster recovery:
1) The servers are virtualized, thereby abstracting the operating system and applications from the hardware.
2) Typically (but not required) the cloud runs on a common set of hardware hosts – and the private cloud footprint can be expanded by simply adding an additional host.
3) Many larger private cloud implementations are running with a dedicated SAN and dedicated cloud controller. The virtualization in the private cloud provides the benefits of bare metal restoration without being tied to particular hardware. The virtual server can be backed up as a “snapshot” including the operating system, applications, system registry and data – and restored on another hardware host very quickly.
This opens up 4 options for disaster recovery, depending on the recovery time objective goal.
1) Offsite Backup – The simplest and fastest way to assure that the data is safe and offsite is to back up the servers to a second date center that is geographically distanced from the production site. If a disaster occurs, new hardware will need to be located to run the system on, which can extend the recovery time depending on the hardware availability at the time of disaster.
2) Dedicated Warm Site Disaster Recovery – This involves placing hardware servers at the offsite data center. If a disaster occurs, the backed up virtual servers can be quickly restored to the host platforms. One advantage to note here is that the hardware does not need to match the production hardware. The disaster recovery site can use a scaled down set of hardware to host a select number of virtual servers or run at a slower throughput than the production environment.
3) Shared Warm Site Disaster Recovery – In this case, the private cloud provider delivers the disaster recovery hardware at a separate data center and “shares” the hardware among a number of clients on a “first declared, first served” basis. Because most disaster recovery hardware sits idle and clients typically don’t experience a production disaster at the same time, the warm site servers can be offered at a fraction of the cost of a dedicated solution by sharing the platforms across customers.
4) Hot Site SAN-SAN Replication – Although more expensive than warm site disaster recovery, SAN-SAN replication between clouds at the production and disaster recovery sites provides the fastest recovery and lowest data latency between systems. Depending on the recovery objectives, the secondary SAN can be more cost effective in terms of the amount and type of storage, and the number and size of physical hardware servers can also be scaled back to accommodate a lower performance solution in case of a disaster.
