The 3-2-1 backup rule is a distinguished and glorified backup method. It appears that every backup vendor has endorsed it with at least one going so far as to call it “timeless.” Even the U.S Government advocated for the 3-2-1 backup; in a US-CERT paper (United States Computer Emergency Readiness Team), Carnegie Mellon recommended the 3-2-1 method.
In technology, mostly what at one point seeming “timeless” at the next moment is pushed to the scrap heap of history. In other terms, it’s time for version 2 of the 3-2-1 backup strategy. While it is not straightforward as the 3-2-1 backup strategy, there are various strategies ranging from 3-1-2 to 3-2-2 and even a 3-2-3 backup configurations that deserves to be considered by modern agile businesses.
3-2-1 backup strategy states that you should have 3 copies of your data (your production data and 2 backup copies) on two different media (disk and tape) with one copy off-site for disaster recovery. This is illustrated in the figure below.
The 3-2-1 backup strategy illustrated above was an advancement on the tape-based strategy where you had only one media copy and you took it offsite. This was perceived as an advancement then. However, inherently limited due to the limitations in technology.
With older continuity and backup protection, 3-2-1 was the best strategy. The second media type was typically tape and depending upon the size of the company using the 3-2-1 backup strategy the options for getting it offsite stretched from hiring a service such as Iron Mountain vs placement at the back of your car. As cloud-based backup companies evolved, they offered 3-2-1 backup via the cloud (and for the most part ignored the second media type in favour of the cloud.) This is depicted below.
Remember to ask your backup vendor specifically if they offer a 3-1-2 as shown or if they provide only a 3-1-1 (one copy in the cloud.) Do not accept only a single copy in the cloud, it doesn’t offer the protection afforded by modern continuity and backup solutions.
The 3-2-2 backup method consists a mix of local and cloud-based protection to be provided. With the backup strategy, you achieve continuity through the use of both the cloud and a local second media type. The cloud provides you with both continuity and extended retention. The local second media provides you another copy of what you have in the cloud in a 3-2-2 backup strategy as illustrated in the figure below.
The final backup strategy is a variation of the 3-2-2 backup strategy called the 3-2-3 backup strategy as depicted below
The backup strategy enables one to execute disaster recovery in two different methods. First, with the cloud or secondly with physically moving data offsite. Through this approach, the cloud does not receive all backup copies, instead they are split between the first and second media type locally. Regular IT administrators who apply this backup strategy are trading additional labour (physically moving data offsite) for lowered expenditure on WAN bandwidth.
With a word of caution, many continuity and backup vendors do not offer this kind of flexibility. If you presently don’t require this type of flexibility, you may in the future. So, ensure that your continuity and backup vendor have an emphasis on offering you support for your agile IT environment.