APCu generates occasionally Internal Server Errors / 500

I tried to optimize a nextcloud instance. Among others I tried to use APCu.

So far so good, but I occasionally get Internal Server Errors “unable to complete the request” / 500 errors in the tests. In other moments, everything loads normally. Some series of tests have no errors, some have repeatedly some. Unfortunately, the protocol remains silent on this point.

Is this a performance / speed problem with the server or Nextcloud installation?

  • Nextcloud 18.0.3
  • PHP 7.4.2
  • OPcache 7.4.2
  • APCu 5.1.18
  • FreeBSD 12.1

In general an addition for system information like

would be nice to check.