I always describe the interview process as being a lot like being on a blind date. You shouldn’t be looking to stump someone during an interview. Memorization of obscure facts such as database mirroring is only supported starting with SQL 2005 SP1 is not going to translate to success in a DBA role.
The DBA role does not require you to know the answer as much as being able to find the answer. A good DBA will be able to teach, and train, others. This will require a good deal of patience.
The five questions I posted previously helped you get an idea of the skill level of the candidate. Since that post came out two years ago the industry has changed quite a bit. Virtualization is more common. The Cloud is here to assimilate everyone. Despite all that has changed there remains some core skills needed by any successful DBA: good troubleshooting skills, communication skills, a sense of humility, the ability to listen, the ability to work well with others, and the ability to work well under pressure with multiple deliverables (including the middle-of-the night disasters).
Today I wanted to offer up five additional questions for you to use when interviewing a database administrator. They will help you learn more about the candidate’s practical work experience better than any resume ever will.
1. What is the most important job function for a database administrator?
This question gives you the opportunity to understand what “being a DBA” means to the candidate. If you are conducting the interview then I will assume you know that (1) you have an idea of exactly what duties you expect the DBA to perform and (2) that a DBA wears a lot of hats depending on the shop they came from. They may be more server and hardware focused and rarely write T-SQL. Or they could have been more on the development side and knew how to do a restore but have never racked a server in their life.
You need to know a bit more about what their practical experience has been. I’m talking about hands-on experience, too. If they haven’t touched it, then it doesn’t count as experience. It counts as classroom learning, but that’s about it. And if that classroom learning didn’t have a hands-on lab it counts as listening, maybe. Once you can get an understanding of the tasks they have been doing you can also understand if their understanding of what is most important matches your expectations.
For example, to me the most important function would be the ability to recover data to a specified point in time. That’s what I expect a DBA to get done. That may not be what you want. But unless you ask the question you will never know how much gap exists between you and the candidate.
2. Hyper-V or VMWare?
Similar question to asking someone if the prefer Kirk or Picard, depending upon the role you have in mind for your DBA you may expect the candidate has some experience with virtualization. It would be good to know if they have practical, hands-on experience with any particular type of virtualization software. Unless you are expecting them to be your VM admin, I wouldn’t worry too much if they only have experience with one or the other. In other words if you are a VMWare shop I wouldn’t think that the candidate only using Hyper-V would be a deal breaker for you. The important thing here is that they can demonstrate some familiarity with the concepts of virtualization, if needed.
This may be one of the more technical discussions you have, as the answers could lead you down a path of talking about network cards and cable, virtual switches, storage, RAID, virtual CPU, live migrations, etc. Listening to the candidate share some war stories is good way to get an understanding of their true skills.
3. How do you plan for upgrades?
Most database software vendors release new versions within 2-3 years of the previous version. At some point, no matter how slow it may take, a company will upgrade to the newer version. If the candidate has not been around long enough in IT to go through an upgrade then you’ll want to know that up front.
I’m not saying that not having done upgrades is a red flag. There are plenty of reasons why a company may have not done any upgrades at all. What I am saying is that having someone go through the experience at least once is quite valuable. This is a good discussion point for things like upgrade in place versus installing something new. You get to see how they approached the idea of upgrades and migrations. You can talk about project plans, timelines, lessons learned, etc.
You may even learn something new, too.
4. What trends do you see coming in the next 3 years that will impact your role the most?
This is along the same lines as “how do you stay current”, but I think it is better because it gives me some insight into how the candidate can ascertain the costs, benefits, and risks in their role as a DBA. It’s too easy to make up answers about how you stay current. It’s harder to offer insight into industry trends. Doing show shows vision and creative thinking.
This is also your opportunity to see how well the candidate reacts to new things. A good DBA must be flexible to new ideas and concepts. If you find someone too rigid in their thinking then consider that a red flag. You want a DBA that leans more to the “we can do that, and here’s what it will take, and here’s the risk” versus the “never touch that thing over there because I’m afraid of change”.
5. What frustrated you most at your previous job?
Lastly, there’s a reason why the candidate came to your office today, and you need to know more about why. I like how this question is framed better than the traditional “why are you leaving your last job”. Asking them about their frustrations allows for you to get some insight as to what they are looking for in their new role. This allows for you to know rather quickly if they are likely to be frustrated with you as well. For example “I was frustrated with being called every night” won’t bode well for them if you are expecting them to also be on call.
This also gives you some insight as to how they work with others. If they sit there and bad mouth everyone they used to work with, that’s a huge red flag about the working relationship you can expect as well.
In addition to the questions, and the conversation that ensues, you are also going to want to evaluate the candidate in other areas. For example, you can look for certain things that would have the candidate stand out among the others, or where they fail to measure up.
And there you have it, five additional questions to ask of any DBA in an interview. You can alter these to fit your needs for whatever role you are trying to fill, just keep in mind that you want to frame everything in the form of a conversation. After these questions you can move into more targeted questions with any candidate that has done well.
If you can follow this outline and have a good conversation then you are going to be able to identify the right candidate.