By Jim O’Connor, Senior Product Marketing Manager, EMC Backup Recovery Systems
When a storage disaster occurs there are two questions that immediately come to mind: Where’s my data?!, and How long will it take to restore it?! These critical questions can be answered by understanding and evaluating two specific metrics: Recovery Point Objective (RPO) and Recovery Time Objective (RTO)
- RPO looks backward to the last backup; it’s a measure of how much updating will be required between that point and the current state.
- RTO looks forward (eagerly) to the moment of resumed operations. When a disaster occurs, this is the one that the business line managers will be obsessing about.
So, Where’s my data? It depends.
- How long ago was the system backed up?
- How often are incremental backups conducted?
- Are backups prioritized for mission-criticality?
How long will it be before we’re up and running again?
- How long before all the data arrives at the DR site?
- How long will it take to load the backed-up data?
- When was my last backup (or Recovery Point)?
The answers to these questions depend upon your backup technology. Everything is related to how much transactional activity occurs after your last backup and how long it takes to get that data after your next system failure.
Hours vs. Days – The Benefit of Virtual Tape Backup
A move to virtual tape backup can reduce RTO and RPO by many hours, and often days. The first thing that is eliminated is the need to physically transport information anywhere. So the 24, 48, 72 or 96 hour delays in transporting tape backups– after backups or disasters — are simply gone. When systems are backed up to virtual tape, the backup is securely encrypted and transmitted via TCP/IP to the interim or DR site. TCP/IP verifies that the backup arrived, and your data is exactly where it needs to be if an adverse event occurs.
In the event of a system failure, the data is already at the DR or interim site. Finding data sets is simple; each data set has its own unique VOL-SER on disk, and there is no need to mount reels on spindles. The system finds virtual tape volume #1, mounts the data set, and moves on to the next step automatically, with sub-second response time. The recovery begins immediately. The tape management system loads the files rapidly and automatically, and the system is restored in a few hours. In the world of real tape, it would normally take roughly 24 hours to get a full, restored, functioning system, which is on top of the considerable time already saved waiting for tapes to arrive from the offsite storage facility.
Should you consider a virtual tape solution?
The virtual tape backup solution was devised to allow mainframe-based companies to make use of the technological advantages of disk-based storage in a plug-and-play manner. The ancillary advantages are considerable, as well: the prioritization of data allows users to tune their RPO and RTO, on top of the highly dramatic reductions of both when transportation and tape-based restoration is eliminated. This only serves the business mission and compliance in ways that make life much easier for IT.
If you are attending Share in Anaheim (Aug. 6-10) please stop by our booth (#302) to discuss EMC’s mainframe virtual tape libraries.