Many companies are moving their services to the “cloud” and with this move comes the need to understand a critical term that separates the proverbial men from the boys! This term is high-availability (HA) which simply means any system or component that is continuously operational for a desirably long length of time. HA is often paired with the acronym SLA which means service level agreement. This agreement guarantees to the customer an up-time based upon a variety of metrics. SLAs are essentially a service contract in which the cloud service provider predefines what is acceptable uptime with stipulations as to what happens when performance falls below these levels.
When you use common metrics to define these levels, you can ensure that your cloud vendor’s performance remains in line with your business needs. The common metrics include percentages like 95%, 97%, 98%, 99%, etc. While these percentages may seem high and acceptable, hey, a 95% is an A in college right, there is actually a great bit of downtime when these percentages are translated into days, hours and minutes. Pingdom.com a very popular uptime monitoring website created a helpful cheat sheet to easily convert SLA uptime percentages to monthly and yearly downtime in days, hours and minutes.
Download the chart here: Pingdom Uptime & Downtime Conversion Cheat Sheet
So what should your business be looking at? Tech Tripp recommends providers who guarantee “four nines” (99.99%) uptime guarantee. We also want to ensure that the proper reporting procedures are in place to show this uptime was met to the end user. Further, we always look for providers who publish their uptime results on a regular basis – transparency is a must! Lastly, the SLA must be financially backed meaning, the provider must start paying you a percentage of your contract when the SLA is not met.
In conclusion, when it comes to SLAs, it is worth spending the time to get them right. Review your expectations with your cloud provider and thoroughly read the SLA. Remember that SLAs often have caveat provisions for Acts of God, DDoS attacks, as well as planned maintenance. As with any long-term relationship, it is best to have the expectations communicated as clearly as possible at the beginning of the relationship so if things do break down, it helps to have the remedy there in black and white without the need for negotiation.