For years customer have been facing problems with backup windows, Recovery Point Objectives (RPO) and Recovery Time Objectives (RTO). The falling cost cost of storage has fueled the use of disk to increase the speed of backups and provide a potential solution to backup window, RPO and RTO issues. Customer today are leveraging the disk based backup solutions to augment their existing tape solutions in an effort to decrease backup time and recovery time as well as prolong investments in aging tape technology. Disk based backup solutions have taken numerous forms, leveraging ATA or LC-FC (low cost fibre channel) is a popular low cost solution that can normally be implemented in conjunction with an enterprise storage consolidation or integrated into an existing storage strategy.
The use of ATA or LC-FC can be a very economical introduction into the world of B2D. Often larger organizations shy away from traditional backup to disk because of the associated process change required and the potential increase in operational complexity. Organizations looking to benefit from the speed of disk without the need for process change may consider a VTL (virtual tape library) strategy. Virtual Tape also offers operational simplicity, in many cased native IP based replication, compression and/or data de-duplication. VTL devices are purpose built and optimized for backup this makes VTL a compelling choice. The caveat with VTL devices is that the simplicity of an emulated tape device also offers the many of the limitations and licensing costs associated with physical tape.
Organizations should also consider SLA requirements that typically encompass backup windows, RPO and RTO. What will the backup data flow be once a B2D solution is implemented? Will the architected B2D solution meet all the requirements of the SLA? In most cases the current state may look like D2T (production disk to tape), D2T2T (production disk to onsite tape copy to offsite tape copy) or D2Clone/Snap2Tape (disk 2 array based clone/snap 2 tape). Once a B2D strategy is employed the flow may look like any one of the following D2D2T, D2VT2T, or D2Clone/Snap2D2T, etc… The point here is that there are more ways than ever to implement backup solutions today, the pros and cons of each solution should be considered relative to the desired and/or required SLA, RPO and RTO.