Happy Belated Birthday to my Zimbra Servers
This success story is a long time in the making.
I first started using Zimbra in April of 2006. It was mainly just a test for a possible migration from Exchange, but stayed as a development project for over a year. During that time I received plenty of help on the forums and wiki pages while messing around with configurations and custom solutions my company would require if we did migrate to Zimbra. The first production server was put into service on Memorial Day weekend 2007. We were using the Open Source edition and the Zimbra Cold Backup script. That is when I ran into my first real problem.
Back in the those days the migration application for Exchange wasn't the best it could be but it mostly worked. The biggest problem was the way it processed attachments and calendars from Exchange. The attachment bug was fixed in the very next dot release of Zimbra, unfortunately its was too late for me. We powered through the problem by archiving all the mail in Exchange as .psts and retrieved the document/file for the user until it was no longer needed. Calendars however were a bigger headache as some appointments, thanks to Outlook, can have a million line breaks (“\n”) in it. In Outlook and Exchange this looked fine to the end-user. In Zimbra the appointment looked fine in the Webmail calendar but when using Lightning, as we switched to a combo of Outlook (IMAP) + Sunbird and Thunderbird + Lightning, this caused huge .ics files that would locked up systems when trying to view them. This took a lot of manual troubleshooting and hand editing to fix, but it was eventually fixed.
So we dealt with this scenario for about 4-5 months and then the CEO and Sales department insisted that they needed Outlook to work with all the bells and whistles. This was when we moved from the Open Source edition to the Network Edition. With this upgrade, which I believe took place alongside an upgrade to ZCS 4.5.x, my job as an administrator became much easier. Outlook 'worked', backups were easy and a ton of bugs had been fixed from 4.0 to 4.5. At this point things were so solid I rarely even checked the servers anymore.
Then I upgraded to I think 4.5.8 or 4.5.9, one of these had the Tomcat/Java High CPU bug in it. I had to keep a terminal constantly logged into the box running top and as soon as I felt a slow down in mail delivery I knew I would have to kill zmlogger or wait it out if the timing wasn't crucial. I dealt with this bug until we upgraded to 5.0.2. Once again things were solid and we didn't really run into any of the bugs that were being fixed during the point releases up to 5.0.9. Two weekends ago we upgraded to 5.0.9 and with it gained iPhone support and tons of features/tools/fixes that I didn't know was a problem, however my users appreciated the fix.
As of this writing we have 5 Zimbra servers deployed, 3 Production and 2 Development. All I can say is I will never go back to Exchange and the higher ups couldn't be happier with the migration more than a year later.