Bumping this as this issue has come back to bite us many-fold on Patch Tuesday. Hoping that there is a solution.
We just upgraded from Build 7503 to Build 7523 using the .EXE and also installed KB4569751 Cumulative Update for .NET Framework 3.5 and 4.8 for Windows Server 1909 on the same evening (so I can't really tell which is to blame atm) and things went from bad to worse (so worse that SM doesn't really work).
We are now getting @ 6 SM crashes per day. Worse is that for the first two hours SM restarts after crashing it is barely functional while it builds up RAM (resulting in over 2+ hour delays in delivery of email). The SmarterMail service starts out a little more than a GB and keeps adding memory until it gets to @ 8.5GB where it can finally function properly. In the meanwhile you can have only one of the following, but not all 3:
- Delivery of Email
- Mailbox Indexing.
- Anti-Spam & Anti-Virus Checking (we only have Message Sniffer, Null Sender, SpamAssassin and ClamAV running on this server as our Incoming Gateways handle all the other Anti-Spam Checks).
CPU is pretty stable at < 50% (even with 30,000-120,000 messages stacked up in the Spool queue because our SM installation just can't cope with doing mail stuff anymore...although SM Spool Dashboard can only show a max of @ 2500 msgs in the Spool at a time) but Memory usage will work it's way up to 80% before crashing again.
We are running Windows Server 2019 on Hyper-V with Dynamic Memory. As we are crashing so frequently at this point it doesn't matter if we have Out-of-Band maintenance because SM is constantly down now. I will disable the Dynamic Memory tonight to see if that makes things any better...otherwise we will try to roll back to Build 7503 that still crashed frequently but recovered immediately from crashing and did it's job.