[systemd-devel] Limitation on maximum number of systemd timers that can be active

[Lennart Poettering]

On Mi, 03.02.21 12:16, P.R.Dinesh (pr.dinesh at gmail.com) wrote:

> Do we have any limitation on the maximum number of systemd timers / units
> that can be active in the system?

We currently enforce a limit of 128K units. This is controlled by
the MANAGER_MAX_NAMES define, which is hard compiled in.

> Will it consume high cpu/memory if we configure 1000s of systemd timers?

It will consume a bit of memory, but I'd guess it should scale OK.

All scalability issues regarding number of units we saw many years
ago, by now all slow paths have been fixed I am aware of. I mean, we
can certainly still optimize stuff (i.e. "systemctl daemon-reload" is
expensive), but things to my knowledge having a few K of units should
be totally Ok. (But then again I don't run things like that myself, my
knowledge is purely based on feedback, or the recent lack thereof)

Lennart

--
Lennart Poettering, Berlin