How to configure nsup-period if default-ttl is non-zero (v4.9+)?

While trying to upgrade our aerospike clusters from 4.5.3 to 4.9 (and eventually 5.0), the server doesn’t start if default-ttl for a namespace is not 0. The documentation says to have either nsup-period set to non zero value or allow-ttl-without-nsup to be set to true in such cases. It also strongly recommends against the latter option but I couldn’t find any documentation on how to tune nsup-period without messing up write performance.

Any tips on configuring nsup-period would be helpful? Right now, on our 4.5.3 clusters, we leave nsup-period as the default value (rather we didn’t even know such a thing existed) and the server doesn’t have any problems starting up even with non-zero default-ttl

You should be just fine keeping the nsup-period as you have had it in your existing clusters. As soon as you reach a decent number of records (hundreds of millions or so I think), nsup would take longer than the (previous default) of 2 minutes to complete a sweep of the index… it would therefore continuously run in the background and should not impact performance for typical workloads the system was sized for (it would impact one CPU core).