[Koha] Diagnosing sudden increase in CPU usage (no images)

Hey everyone, Was hoping for some guidance on where to start diagnosing an increase of CPU, disk and network usage on our Koha instance. The culprit is seemingly plack (/etc/koha/plack.psgi) & the Koha perl API (usr/share/koha/api/v1/ app.pl). No changes were made, updates nor configuration, and according to our monitoring started on the 23/03. Have gone from sitting at around 0% CPU idle, to ~20% on the 23rd and now averaging around 70%. Any ideas on where to start? Thanks in advance, Justin Dowswell (he/him) Technology Coordinator Tenants' Union of NSW 02 8117 3721 tenants.org.au