Something I have been wanting to do a blog on for a few months now is the difference between DR and BCP as I still feel that there is confusion over the difference between the two. Another reason for writing this is simply that the UK is in a very strange position where BCP is likely to take on a whole new meaning with the upcoming fiasco called Brexit. More on that in another blog.

DR = Disaster Recovery, something has broken so badly that it needs to be recovered. This could be an exchange server that has failed or a site that has had a fire. In those scenarios you will have systems down, potentially damaged hardware and will need to either recover from backup.

BCP = Business Continuity Planning, firstly this is an awful acronym as it suggests that business continuity only needs to be planned and never needs to be tested. With the current world situation, it is clear that the occasional practice always comes in useful.
BCP is all about continue to allow staff the ability to do their jobs if a site or system is not available. BCP could even be considered as in play when a node of a cluster goes down as the work of the business continues even while the service is degraded due to the node failure.

In IT, a lot of DR and BCP planning is not formalised, it's pretty obvious that if an office loses its internet connection the people there will still need to be able to do their jobs so the most likely outcome would be to send them home to use the VPN. Same for a serious server issues. If an AD server has a fault you should have a second one to take on the load but the fault has to be fixed. Technically, you are into BCP here - the business continues to run as AD isn't a single point of failure, but the service has still suffered a failure as it is not working as planned.

DR always incorporates elements of BCP whereas BCP can be initiated without any need for any sort of preceding IT disaster as was seen with the UK wide COVID-19 lockdown. At that point, the offices were perfectly usable but outside elements forced the enactment of company BCP practices to allow the continuation of business (or as much as could be continued) without access to the usual office-based resources. I should also note that BCP goes far beyond the IT department.

BCP needs to involve every team within the business as they all have their unique requirements that can affect their ability to work remotely and it is only when experiencing such an event that the process is put to work often with a large amount of stress, quick fixes and other 'sticking plaster' solutions that often go undocumented and so increase tech debt and just become something of a time bomb for the future.