Zimbra Collaboration Server is a fully-featured open source messaging and collaboration application that supports email messaging,  group calendars, blackberry sync and other features using an advanced Ajax web interface that enables tool tips, drag-and-drop items, advanced searching capabilities and right-click menus in the UI. The software consists of both client and server components. Two versions of Zimbra are available: an open-source version and a commercially supported version (“Zimbra Network”) with closed-source components such as a proprietary connector to Outlook for calendar synchronization. Zimbra has been bought over from Yahoo by Vmware and they have recently released ver 7 of the Zimbra Open source and Network editions on their website. The Zimbra Server uses several open-source projects e.g. Postfix, MySQL, OpenLDAP, Apache Tomcat (replaced by Jetty since 5.0), ClamAV, SpamAssassin, AMaViS and Amavisd-new, DSPAM, Aspell, etc. It exposes an Application programming interface (API) to all its functionality and also is an IMAP and POP3 server. The server runs on many distributions of Linux as well as on Mac OS X.   Zimbra can synchronize mail, contacts, and calendar items with open-source mail clients such as Novell Evolution and also with proprietary clients such as Microsoft Outlook and Apple Mail, but only through proprietary connectors available exclusively in the commercially supported version (“Zimbra Network Edition”). Zimbra also provides native two-way sync to many mobile devices (Nokia Eseries, BlackBerry, Windows Mobile, iPhone with 2.0 software).   Zimbra can be an ideal mail server for your organization if you are having more than 50 users and if your users require the advanced collobaration features which a groupware can offer (calendaring, shared folders, appointment tracking, web based UI, etc.). As it has full POP3 and IMAP support alongwith a robust spam filter (it segregates the suspected spam mails in a junk folder so that users can review the mails and mark the false positive mails as ‘not junk’), its very useful at organisations who want to stomp out spam mail but need the option to verify the mails which have been tagged as spam (akin to most web based email services). We have successfully implemented Zimbra for several of our clients in a virtualised environemnt and  it works well with just 2 GB RAM and Multicore processor for upto 100 users. We have also recently migrated one of our client’s 12 GB mail box to the Zimbra Server with a single script as given below  

To migrate the mails, first you need to create all your mailboxes in zimbra server.

And after that move all your messages from Plesk Server to Zimbra server in a same folder structure

To backup from Plesk server follow the steps.

# cd /var/qmail/mailnames/

# tar -zcvf /your/path/domain.tgz domain.com

Now move the backup file (domain.tgz) to Zimbra server with SCP or Samba share (or any other method) whichever is available. Go to the path where you have copied the backup file and extract the backup file.

# cd /your/path

# tar -zxvf domain.tgz

It will look like something as below when you list the extracted folder.

domain.com/user1

domain.com/user2

Now copy the below script in domain folder as ‘mailexport.sh’ and grant execution permission and run the script. It will add all your mails from Inbox and other custom folder to Zimbra server mailbox.

#!/bin/bash

#

# Maildir to Zimbra import

# Drop in your user root and run as superuser.

#

domain=”domain.com” # change to your domain!

for user in `ls -d1 */|sed s/\///`

do

echo

echo “User $user”

echo

#

#

find $user -maxdepth 10 -type d -name cur | while read line;

do

folder=`echo ${line}|cut -f3 -d”/”|sed s/\.//`

line2=`echo ${line/%cur/new}`

echo “FOLDER $folder”

if [ “$folder” = “cur” ]

then

/opt/zimbra/bin/zmmailbox -z -m $user@$domain addMessage Inbox $PWD/$user/Maildir/cur

/opt/zimbra/bin/zmmailbox -z -m $user@$domain addMessage Inbox $PWD/$user/Maildir/new

else

if [ “$folder” != “Sent” ] && [ “$folder” != “Drafts” ] && [ “$folder” != “Junk” ] && [ “$folder” != “Trash” ]

then

/opt/zimbra/bin/zmmailbox -z -m $user@$domain createFolder “/$folder”

fi

/opt/zimbra/bin/zmmailbox -z -m $user@$domain addMessage “/$folder” “${PWD}/${line}”

/opt/zimbra/bin/zmmailbox -z -m $user@$domain addMessage “/$folder” “${PWD}/${line2}”

fi

done

All done now you can get your old mails within the Zimbra server. If you are looking at an alternative messaging alternative to either Google Apps, MS Exchange or simply need a more robust messaging solution, the Zimbra collaboration suite (open source or network editions) could be a suitable solution to meet your needs.