CPU thrashes after rsync

[adrianshort]

I'm running version 20220131195043-17.5.0-6d8b434-linux/arm on a low-spec Raspi model 1B+ (650MHz CPU, 430MB RAM).

The site is enabled and serving some static pages to the web.

After rsyncing from my local machine to the server, one of the site processes goes haywire and thrashes the CPU to 100% for several minutes, making the site unable to serve any requests.

It also eats a lot of RAM while doing this, around 2-3 times the usual amount when simply serving pages. So this bumps the RAM usage from around 70MB to over 200MB.

Except for a few minutes after an rsync the site works fine.

This is a test site with effectively no load. Any ideas?