We have 2 * Exchange 2019 servers running in a DAG with approx 11,000+ users. To send out urgent notifications we have a Distribution group with all users that we send out to. We do not want a 3rd party company. There are several departments that use this DL too that have the autority. Our organisation is linked with 2 other organisations each with their own DAG but 1 AD/Exchange environment.
When we send out to this DL, there is a lag in users' Outlook experience and we notice the Disk Queue Latency jumps up to around 5-10 for about 5 minutes and we can see the message queue has up to around 100 messages per DB.
What I am look for is a way to Throttle either the sending mailbox (in messages per minute and not per day such as the recipientratelimit setting) or the 20 mailbox databases from accepting such a large burst. Exchange databases are spread over 2 drives with separate log drives. Mailbox totals are around 13TB.