Editing Business continuity planning (section)

====Consistency====
When more than one system crashes, recovery plans must balance the need for data consistency with other objectives, such as RTO and RPO.
<ref name=OpsBLog.Consistency>{{cite web |url=https://www.opscentre.com/blog/2016/03/22/recovery-consistency-objective |title=The Rise and Rise of the Recovery Consistency Objective |access-date=September 9, 2019 |date=2016-03-22 |archive-date=2020-09-26 |archive-url=https://web.archive.org/web/20200926060225/https://www.opscentre.com/blog/2016/03/22/recovery-consistency-objective/ |url-status=dead }}</ref> '''Recovery Consistency Objective''' (RCO) is the name of this goal. It applies [[data consistency]] objectives, to define a measurement for the consistency of distributed business data within interlinked systems after a disaster incident. Similar terms used in this context are "Recovery Consistency Characteristics" (RCC) and "Recovery Object Granularity" (ROG).<ref>"How to evaluate a recovery management solution." West World Productions, 2006 [http://www.thefreelibrary.com/How+to+evaluate+a+recovery+management+solution-a0147748661]</ref>

While RTO and RPO are absolute per-system values, RCO is expressed as a percentage that measures the deviation between actual and targeted state of business data across systems for process groups or individual business processes.

The following formula calculates RCO with "n" representing the number of business processes and "entities" representing an abstract value for business data:
<math>\text{RCO} = 1 - \frac{(\text{number of inconsistent entities})_n}{(\text{number of entities})_n}</math>

100% RCO means that post recovery, no business data deviation occurs.<ref>{{cite web |author1=Josh Krischer  |author2=Donna Scott |author3=Roberta J. Witty |title=Six Myths About Business Continuity Management and Disaster Recovery |publisher=Gartner Research | url=http://www.gartner.com/it/content/868800/868812/six_myths_about_bcm.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.gartner.com/it/content/868800/868812/six_myths_about_bcm.pdf |archive-date=2022-10-09 |url-status=live}}</ref>