How to set SLO for operations that are dependent on file size?

Question

I have an endpoint POST /upload that uploads file into my storage. The response time is dependent on the file size (the bigger file, the longer it takes to respond with 200). How should I set a Service Level Objective (SLO) with this endpoint? Any suggestion?

Answer 1

I would suggest looking at it at a higher level first. Usually, you measure response time from the server where it mostly depends on the server-side. Whereas uploading files to storage mostly depends on the client (network bandwidth). So it depends if you want to measure client performance upload speed or not.

But if you still want to measure performance SLO I'd suggest measuring performance against specific size. Say if you know for example average is 500kb and 90% is 1Mb then measure performance up to 1Mb of files.