First things first - is mysql working ? If it is you should be able to find stuff manually - otherwise you are left to thrawl through files on the file system.
I don't know all the ins and outs - but zimbra basically stores pretty much everything as an MSG file. It uses indexing in the database to figure out how to interpret each file.
The files are stored on a per user basis on the file system in folder /opt/zimbra/store/
I think for a single server, they will always be in sub-folder 0 from there (not sure if the 0 relates to the server or the domain) so
Within this folder, there is a sub-folder for every user you have created. And within each of those folders are a set of subfolders that actually contain the "message" files. This is where you will need to start looking.
To check mysql, use "su - zimbra" to become the zimbra user, and run mysql
If it is not running, look through the startup script to see if you can find the startup command and try to start it.
If mysql is running, issuing the command "show databases;" will list all the mysql databases on your system. All the ones named "mboxgroupNN" are the individual databases for each user that contain the indexes/headers/etc for all items in their store.
The database named "zimbra" contains the user account information.
issue the command "use zimbra;"
then "select * from mailbox;"
this should give you a list of the mailboxes.
Look for the one whose "comment" field is the email address you are looking for. Note the group_id associated with that account. This will be the value to go into the NN of the user database name. So if it is 3, you will be using database "mboxgroup3" to search for your items.
issue the appropriate command "use mboxgroup3;" (or whatever number is appropriate)
Once connected, issue the command "show tables;"
Here you can see a list of the tables in that users database.
Use "describe mail_item;" (or whatever other tables you want to look at) to figure out the sql query you will need to search for items.
If it is briefcase - or email - I believe you need to search on "subject" - for briefcase, the uploaded file name appears to be stored as the subject field.
So, if you are looking for a file named "LoginIds" you would need to issue the command
select * from mail_item where subject like "%%LoginIds%%";
The reply should list the details of the mail store item - or items that match.
As far as I can tell, there are 2 fields that are needed to identify the actual mailstore file that contains the file you need (id and mod_content)
so you could refine your select down to just
select id,mod_content,subject from mail_item where subject like "%%LoginIds%%";
This will output something like this
Given this data, you can now put together the file name you need to search the store for.
mysql> select id,mod_content,subject from mail_item where subject like "%%LoginIds%%";
| id | mod_content | subject |
| 36960 | 148094 | LoginIds |
1 row in set (0.01 sec)
It is made up of "id"-"mod_content".msg
So, go to the folder
and search for a file named 36960-148094.msg
I believe for a briefcase file, if you just make a copy of the file to the "subject" name you should then be able to open the file with the appropriate application.
cp 36960-148094.msg LoginIds
I hope this helps get you started at least.
Good luck !