IT is under constant pressure to reduce recovery point (RPO) and recovery time objectives (RTO). Users and applications owners want to set these objectives at zero. While a zero RPO/RTO is a possibility the cost to get there is enormous. Data has to be synchronously written and acknowledged in two locations before the application can move forward with the next I/O. To not impact performance means this configuration requires two high speed storage systems, a high speed connection and more than likely a fairly complex and also expensive, clustered server configuration. If IT can convince the organization to tolerate just 15 minutes of outage the savings are enormous.
It used to be when it came to meeting recovery windows IT only had two options, really fast via synchronous mirroring or really slow via recoveries from backup. The reason synchronous mirroring recovery is so fast is the second copy, by default, has the most recent copy of data. There is no time lapse and as a result no RPO. The second copy of data is also stored on a production class system in an active state. There is no data movement nor conversion from a backup format. Just point to it and go. If you are running a cluster then you don’t even have to point to it, you just go.
Backup is essentially the exact opposite of synchronous mirroring. Data is copied at most a couple of times a day instead of in real-time and the copies are stored on a cost-effective storage system in a backup format. During a recovery data has to be extracted from the backup format and copied across the network to the application’s volume, which may also need to be recreated. The combination leads to RTOs of hours and RPO of potentially days.
Affordable 15 Minute Recoveries
Now though IT has a new option that should generate RPO/RTOs in the 15 minute to 1 hour range thanks to change block backups and in-place recoveries. Change block backups minimally impact the applications they are protecting and the networks they send data across. Their low impact nature means IT can capture data much more frequently, lowering RPO. Solutions with a recovery in-place feature can present an application’s volume directly from the backup storage devices, which means no data has to be transferred – lowering RTO.
With these two capabilities, RPO/RTOs of less than an hour a easily achievable and sub-15 minute RPO/RTO are plausible. While 15 minutes is not zero, the cost difference between a 15 minute recovery objective and a zero recovery objective is massive. A dollar savings that should be very sell-able to management.
To learn more on how to cost effectively meet lower RPO and RTO expectations join our on demand webinar “The Always-on Enterprise Requires New Service Level Objectives“.