Is anybody started using MAPI in Production?
Question asked by Netmate - 1/20/2021 at 12:22 AM
Is anybody started using MAPI for a large number of users (100+ users) on a single server? If yes, then please share your experience. Thanks!

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I'm using it only for 4 user till now and it seems to be good...

I'll follow up to see if there are others that can share experience
Gabriele Maoret - Head of SysAdmins at SERSIS Currently manages 6 SmarterMail installations (1 in the cloud for SERSIS which provides services to a few hundred third-party email domains + 5 on-premise for customers who prefer to have their mail server in-house)
Netmate Replied
Thanks Gabriele! 

We have 200 email users and all are currently using IMAP, but now we would like to roll out MAPI for all users.

Our dedicated email server has 8 Core CPU and 32GB RAM. The average CPU usage is less than 10% and RAM usage is around 16GB. The mailbox size ranges from 5GB to 15GB.

I would like to know whether this server will support MAPI for all users? Also, is MAPI more resource intensive or less resource intensive than IMAP?

Please share your experience if any. Thanks!
Patrick Mattson Replied
I am on the release from December 30, 2020.

I am starting to create the certs and update DNS records.

My roll out has begun at a couple of customers and have hit a snag at one customer on a couple of devices. One person using Outlook 2013 would not connect to MAPI and an iPhone would not connect. The Office 365 connected right away.
Outlook 2013 is not supported by SM MAPI service. Only 2016 and up.

So it's normal that it can't work with MAPI.

iPhone needs EAS, it doesn't work with MAPI.
Gabriele Maoret - Head of SysAdmins at SERSIS Currently manages 6 SmarterMail installations (1 in the cloud for SERSIS which provides services to a few hundred third-party email domains + 5 on-premise for customers who prefer to have their mail server in-house)
Ionel Aurelian Rau Replied
We use MAPI in production with Outlook 2016 and 2019 (both click-to-run from the H&B and Proffesional Plus MS Office packs). We have a little over 400 users with ~ 250 connected concurrently at peak.
From our experience, MAPI is the best way so far to sync MS Outlook with SmarterMail, although there are some issues from now and then (most documented here on the community and some odd ones we have tickets opened for).

I personally wish we could get rid of Outlook, but it`s not going anywhere anytime. Moreover, in the past year we`ve had to provide it to almost all employees due to some business requirements. So, if you have Outlook, MAPI is your best bet. If it were not for this, We`d stick with WebMai.
Netmate Replied
Thanks Lonel for sharing your experience.

What is your experience regarding the resource usage in terms of CPU and RAM? Is MAPI more resource-intensive or less resource-intensive compare to IMAP?
echoDreamz Replied
We use MAPI as well, mostly 2016, but quite a few 2019 users as well. The only big complaint thus far is that Outlook does not sync rules with SM and vice versa. Other than that though, it's been smooth sailing for a bit now. We've not noticed anything really different with MAPI in terms of resource usage, especially since SM has changed so much in v17, it is hard to say if it is MAPI-specific.

I can tell you our SM server eats more RAM than it ever has before, our last restart for updates, the SM process was using 52.3GB. Most likely due to all the caching and what not that SM does, which is fine with us, RAM is cheap, I can throw more RAM all day. CPU is lower than ever with all the efficiency improvements that SmarterTools has made to SM, same goes for disk IO.

I personally love Outlook and dedicated apps, I despise web interfaces, as does a lot of our users thankfully. With the exception of the guys who refuse to budge from 2007 and other older than dirt versions...
Ionel Aurelian Rau Replied
We`ve seen about ~ 10 - 15% max RAM usage increase overall, but this varied between builds. A few previous builds ago we had a bit higher usage, but now (Build 7685) it`s back down again. CPU usage is about the same, maybe up to 10% higher. 
We`ve added some some additional signatures to ClamAV and this also increased its RAM usage, but that is another story.
We have sufficient RAM and it would not be a problem if SM used more to do caching or to improve performance - as long as the higher RAM usage is not the cause of memory leaks or other inefficiencies.
I think the biggest impact on performance anyway is the disk I/O. Our data resides on NVMe drives and performance is quite good, especially now after many efficiency improvements.
Our install maybe is not the best showcase as we do not really have that many users (there are many installs with way more than 400 users) but we are quite active and have many different users stressing the Web Interface, Outlook and other clients in various ways.
The most important thing is that issues that we open tickets for are usually fixed in good time, except for those that are the cause of Microsoft products or require Microsoft`s involvement, which are a pain as sometimes these affect higher-ups so there is a lot of pressure. 

Right now SM is quite stable and good for us in general. As long as future updates do not introduce any more major issues, it`s fine.
Netmate Replied
Thanks echoDreamz & Ionel, really appreciated your replies.

All our users are using Outlook 2016, so no issues here. However, many users use 'Rules', so it is a big concern for us.

I think we have to wait until the rules sync issue gets resolved.

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