[systemd-devel] How to scale journald correctly?

[Martin Häcker]

On 13.07.18 17:07, Lennart Poettering wrote:
> journald is designed to just write out what is being thrown at it,
> with the speed the underlying device permits. It is using relatively
> large reception buffers for this, so that clients don't have to stall
> on journald. If you flood journald heavily it will eventually cause
> clients to block though.

Is there a known bug about this in version 219? Because what we see is
that even with a moderate write load of about 100-500 kb / s at some
point journald seems to snap and starts reading and writing at full disk
throughput speed (which is about 50mb/s on our servers).

That smells like a bug to me.

As we're using the long term support version fo SystemD in CentOS 7.5, I
guess that this behavior should be  fixed / discussed / workarounds
documented - but I'm not entirely sure what the right way to proceed
would be here. Please advise.

For reference, I'm referring to the behavior documented in this bug
report: https://bugzilla.redhat.com/show_bug.cgi?id=1599658

Best Regards,
Martin Häcker