Excessive "warning: psc_cache_update:" in the Postfix Logs

theprez1980

Hey All -

I can’t see any performance related issues personally, but in the log files under Postfix, I keep seeing this message and am unsure how to address. I don’t see any disk contention/IO issues, there’s 10 users, 32GB of RAM, and 8 vCPUs allocated so I would think more than enough resources…

warning: psc_cache_update: proxy:btree:/var/lib/postfix/postscreen_cache update average delay is 143 ms

The delay varies but it’s usually around 140 to 150 ms.

Any ideas what’s occurring here and why? This is on version 2025-05, and is running on Debian 12.

Thanks

esackbauer

Maybe storage is too slow (ready times, waiting for IO on physical host level)? VPS too much overprovisioned by greedy hoster?
Lots of spam traffic?

theprez1980

It’s on a dedicated server of mine in a colo datacenter - only two VMs are running on it - Proxmox as the host OS, OpnSense as the VM for the router/firewall, and then Mailcow on Debian as the other VM. IO Delay and load is always under 6% according to Proxmox’s panel. I don’t see any large amount of spam but I can monitor…. perhaps its just expected behavior with rust slinging disks (hard drives instead of SSDs)

esackbauer

theprez1980
Yes, spinning disks lead to higher latency and higher ms. Have you measured the IO from within the VM? Is there a memory leak somewhere that buffers get depleted?