Confused On Maximum Message Size

[soxfan]

I've had Zimbra configured to allow what I thought would be approximately 10 MB attachments to be sent/received. Taking into account some message overhead, I had the "Maximum message size" set to 12582912 kb. I thought everything was working OK, but today I had a user receive a message, with an attachment, which shows in the "Size" column as 10 MB. When she tried to forward the message, adding just a small comment, the message was rejected due to the size. My initial thought was that it had just squeaked through, and now the forward with even a small amount of text had pushed it over the limit. When I did some checking I saw that the attachment is only around 7.5 MB. My next thought was that maybe I had underestimated the message overhead. I did some searching around here on the forums and on the web, and found that the message overhead may be around 30%. So, I bumped up my setting a little, and sure enough the message went through. However, when I looked at the logs on our Internet email gateway server, which is running Postfix, the message size shows up as only 10409006 kb. So, what is Zimbra calculating that made it think my message was over my original max message size limit? Or am I just not understanding something about this setting?

Also, on a related matter, when I went to the Admin panel to change this setting I only saw one "size" setting field. I seem to remember that the used to also be a setting for the maximum size of an uploaded file (not sure of the exact wording). I know I can change this setting from the command line, with 'zmprov', but just curious as to why it's not on the Admin page anymore. Did something change in version 5?

[mmorse]

zimbraFileUploadMaxSize & zimbraMtaMaxMessageSize
[SOLVED] Maximum message size
Bug 23996 - restore the UI field, corresponding to the zimbraFileUploadMaxSize attribute, in Admin console

[soxfan]

Thanks Mike. The bug you noted certainly answers the second part of my question. I'm still confused on the calculation of the message size though. I did look at the post that you referenced prior to creating this new thread. This is where I found the information about the overhead being more like 30% of the message, and the file size referenced in the original post is similar to my situation. But what I don't understand is why the Zimbra server is saying that the message size was greater than my original max setting (12582912 kb), but when I finally got the message through by adjusting the setting the Postfix logs on another server shows the message size as being only 10409006 kb. This isn't comparing file size to message size or anything like that. This is the Zimbra server (running Postfix) saying that the message was bigger than 12582912 kb, but yet another server also running Postfix shows the message size is actually much less than the max.