This week's survey is inspired by this morning's Kimberly+Paul hot-tub conversation around data-dependent routing vs. network load balancing, which then turned to SLAs. Yes, we lead an exciting life .

This survey is a *four*-parter. Part 1 is for each of your databases, which survey option is closest to your target maximum allowable downtime SLA (Service-Level Agreement, a.k.a. RTO - Recovery Time Objective)?

• Survey 1 is if your SLA is based on 24x7 operation
• Survey 2 is if your SLA is based on non-24x7 operation (e.g. allowing for a 6 hour daily maintenance window, the rest of the time we must be available 99.9%)

Part 2 is for each of your databases, what can you actually achieve?

• Survey 3 is your achievement over the last year for 24x7 operation
• Survey 4 is your achievement over the last year for non-24x7 operation

I'll report on the result sometime during the first week of June - as this is a big survey I'd like to get lots of results. Please repost/Tweet/whatever.

What do I mean by that downtime SLA? Well, however you have it defined. It could be that your SLA is an absolute value based on 24x7 operation, or it could be based on the 9-5 work-day. In all cases, what percentage of the defined time does the system have to be available? Note that I'm calling out a 5, 4, and 3 nines of 24x7 as separate answers as I'd like to see how often these occur and can be met.

As always, a big Thanks! for contributing to the blog by responding. Please shoot me an email (Contact button, bottom left of the blog), or ping me on Twitter (@PaulRandal) if you have an idea for a good survey.

PS No comments on this post please (I'll delete them straight away) - please wait for the survey results post to avoid skewing the answers.