So I ran into an issue this week with one of my users. They called complaining that web mail was super slow for them all of the sudden. Upon further investigation their GRP file grew to 1.4GB in size and kept timing out their web session along with all of my users that use web mail. Only way I could get web mail to be responsive again was to restart IIS on our server. Which is inconvenient but, the only way I could get the web interface to be responsive again. For the user that was having the timeout issues, they could not use web mail for the long time period SM was indexing their GRP file. Which took approx 4 hours to complete. I also saw listings in our logs on the server that this users mailbox was locked during this time period.
My proposed idea is this, could there be a way in a future build to have the file attachments separate from the actual GRP files that store them emails themselves? Maybe store the attachments under the users account folder and have it linked via email ID or something similar. If it's possible then situations like what I ran into would be eliminated because just plain text would not take that much room at all and GRP files would be pretty small.
If you want an example of what I ran into, here's the thread I started: https://portal.smartertools.com/community/a87692/smartermail-14_5_5907-huge-grp-file.aspx