When planning your disaster recovery strategy you most likely considered how long you can be without an application and how much of each type of data you can afford to lose or be without for a period of time. These considerations refer to RTO and RPO, Recovery Time Objective and Recovery Point Objective, which go hand-in-hand.
RTO and RPO
The RTO is the amount of time that an organization can go without an application or business process without experiencing an unacceptable consequence. The RPO is the amount of time that elapses during a disruption until the quantity of data lost is excessive or is beyond the business continuity plan’s max amount. According to Wikibon this is often thought of as time between last backup and when an “event” occurred. These goals typically come as a result of looking at the business consequence of applications being unavailable and the impact of data loss.
What Temperature is the Data?
Some organizations have thought that every piece of data requires fast and frequent access and therefore is required to be on sub-second storage. This thought is mistaken according to a study conducted by the University of California, Santa Cruz1 which found that 90% of the data stored on network disk was never accessed in the 90 day period after being stored. It was cold data. Another 6.5% of the data was cool, that is, it was accessed only once. Only a small percent was considered warm or hot data that had more than one access. The recovery time requirement for most of the data was long and didn’t need to be on high expense storage devices. The recommendation: move data to less expensive and less energy consuming storage units…..like tape!
Business recovery planners have been employing tiered storage strategies to help achieve recovery objectives for the varied types of hot and cold data and to address data protection and cost containment. How do disk and tape play in this strategy? Let’s examine the storage resources one company implemented. We briefly mentioned this story in the last BlogBytes but it deserves to be looked at in detail as this firm has implemented a solution that strongly protects data and addresses recovery time objectives to support business continuity priorities.
Help, Our Data is Drowning! One Company’s Nightmare
The bad news: the owners and employees of a large trucking express line were devastated when the company lost its data center to a 4.5 foot flood caused by Hurricane Gaston and a blocked city storm drain. The company’s PC and enterprise servers, storage disk system, network systems, uninterruptible power supplies and generator were destroyed.
The good news: 100% of their data was stored offsite on tape from the previous night’s backup. Although they could recover, there was a disruption to the daily operations and customer service until systems could be replaced and replenished.
With the harsh lesson learned, they were determined to set up a failsafe data backup and disaster recovery process to meet recovery time objectives. It had to do so without disrupting the company’s nightly operations, such as printing invoices and tracking loaded freight. This had to be a comprehensive disaster recovery process to prevent major loss due to disasters and to ensure maximum uptime even for moderate inconveniences, such as temporary power outages.
The solution included:
- The creation of nightly disk flash copies for fast ‘hot’ data retrieval and window-less backup to LTO tape
- Backup 100% of production data to an LTO tape library nightly and move those tapes offsite for ultimate ‘cool’ and ‘cold’ protection
- Global Mirror DR site 1,500 miles away and backup of that site to an LTO tape library – a lights out operation! No personnel at this DR site, it is remotely managed (who said it requires lots of personnel to manage tape?)
In essence, five copies of the data are created and three of those are remote to the primary site and two of those are on LTO tape.
The benefits are plentiful:
- Able to control TCO, access to data and protection of data with a tiered storage strategy
- No production system interruption and ability to meet recovery time objectives for hot, cool, and cold data from flash copies, tape and DR site
- No save window – Set it and forget it
- No production cycles, no operators, lights out operations
- Logical data protection and out of region protection
It may be time for a change! Consider a tiered storage strategy blend of disk and tape to meet your recovery time objectives while minimizing cost and maximizing data protection.