Been searching the web and asking my contacts, but other than some opinions, I'm not finding any kind of numbers nor matrix nor formula to guide on when it's time to add another DBA.
Are there any industry standards for this? Probably a tough question, as every situation is different. Some DBAs manage a farm of hundreds of production instances, but the instances are all identical. Some DBAs manage a very few instances, but also have development and network admin duties. We all know that the DBA career path has breadth.
A Microsoft field engineer once told me that the magic number is 30, as in, 30 applications supported. Some apps are simple, some less so, but if you've got a mix of apps, the fellow said, once you're at 30 it's time to at least consider hiring another DBA.
Obviously I'm looking to justify a recent request for another DBA at my company. Any help is much appreciated. Although I've targeted this for SQL Server DBAs, that's only because that's all I've administrated.