Pumping the Water

Today I learned the valuable lesson of the dry run. Testing out a software upgrade on a test instance proved to be a comedy of errors. Thankfully the audience of that show was only me. If any more people had to deal with the downtime it took for me to solve things, it wouldn't be a comedy to them.

Besides learning that dry runs are crucial in software, I also learned about their etymologic origins. Wikipedia referenced this lovely blog called The Word Detective (which has been going for 26 years as of the publishing of this post). Here's what the Word Detective uncovered about the origins of the dry run:

Beginning in the late 19th century, fire departments in the US began conducting practice sessions where engines were dispatched and hoses deployed, but water was not pumped, thus making the exercises literally “dry” runs. Public exhibitions and competitions between departments also typically centered on such “dry runs.” Conversely, a real run to a “working fire” where water was pumped was known as a “wet run.” In his posting to the ADS list, Doug Wilson found instances of this use of “dry run” dating back to 1893. Just when the term came into more general use meaning “practice session” is uncertain, but it seems to have been after “dry run” was widely used in the US Armed Services during World War II.

What's interesting is that the original dry run seems to miss out on an important part of firefighting — pumping the water. What happened if there was a malfunction in the hose? What if the pumping process got botched? I suppose that's why the dry run was more an exhibition than anything else. And yet it crept into meaning a “practice session.”

I wonder if that is where we make sure we do our best to replicate “pumping the water” in our dry runs — whatever that means. For me it's dealing with upgrading software on an instance that is running with snapshots of production data. Might not be the real deal, the actual “pumping of water,” but as long as you get close enough to know that, when the time comes, the water has a good chance of pumping.