On Jan 2, 2023, at 1:21 AM, Ulrich Windl Ulrich.Windl@rz.uni-regensburg.de wrote:
I am aware that contention with disk I/O can cause problems, so I tried eliminating systemd-journald and rsyslogd in order to test "pure OpenLDAP" response times but was not perfectly successful. I ran slapd in the foreground using "slapd -d 256 ... 2>/dev/null". But then I noticed that systemd-journald still was logging to "session-4.scope". I tried "systemctl stop systemd-journald" and "systemctl stop systemd-journald.socket" and "systemctl stop systemd-journald-dev-log.socket" but was not able to stop systemd-journald from showing up using CPU in "htop". I tried limiting it also by setting RateLimitIntervalSec=1s and RateLimitBurst=1 in /etc/system/journald.conf. This reduced the logging but I still saw "/usr/lib/system/systemd-journald" taking 100% of one vcpu during the performance tests whenever olcLogLevel was set to 256.
Did you try to revert systemd logging to ramdisk only (/run/log/journal/ (or so)) instead of /var/log/journal/?
Apologize for missing this before my earlier response. Looks like Chris tried the debug route. I’m guessing there must be a way to detach the system logging facility completely from the daemon?
If someone has suggestions I’ll run some tests to verify.
Thanks
— Shawn