Hey John,
While we don't have immediate tools or documentation on the capacity guidelines to avoid these - i would suggest (if you have a contact) to reach out to your Cisco Account/Systems engineers who can review the loads/capacity you're looking at so ensure your systems can be run safely.
The maximum values can really differ due to:
- size of emails coming through
- how the emails are structured/crafted
- what features you'll be employing on the filtering, minimal? or very high threshold and every type of scanning available
all of these and more will determine the throughput on the ESA as well as CPU and memory usage.
From my experience i've seen some devices handle up to about ~80 emails per minute on the C370 while using the defaulted values and thresholds which are suggested for the device very safely - then i've also seen some devices handle several hundreds more as there was minimal scanning done.
But there has been circumstances with unique and larger emails, different forms of attachments coming through and aggressive scanning where the ESA may be pushed a bit more than we'd suggest with lower email throughput, but the type of email vastly differing.
There are many factors to consider.
Thank you,
Matthew
