Harddisk failure - how to save as much as possible?

[mfehr]

I wanted to prepare my Zimbra server for an upgrade to 7.1.4. Before upgrading, I wanted to backup the VMware image in which Zimbra runs. Something went wrong and I have the worst case. Backup not successful and the disk image is damaged as well. - So, I have the following situation:

• The latest backup is 3 months old :-(
  
  
• The number of accounts is luckily low. It's about 15 accounts
  
  
• IMAP clients (Mac Mail on OS X Lion, iPhone and iPad) have some mail cached
  
  
• CalDAV clients (iCal on OS X Lion, iPhone and iPad) have some calendar entries available offline
  
  
• CardDAV clients (Address book on OS X Lion, iPhone and iPad) have addressed cached local
  
  

What happens if I bring the old backup online? Will IMAP, CalDAV, CardDAV be able to restore newer documents back to the server?
How can I export IMAP, CalDAV, CardDAV data to save as much as possible?
What do you think of the following approach:

• Recover from the backup
  
  
• Rename all accounts temporarily on the the client
  
  
• Create new accounts on the clients with the proper account names
  
  
• This allows the client to receive the old mail plus new mail that got delivered in the mean time
  
  
• Copy data from renamed account and paste it to the proper one
  
  

Any help is welcome!

[mfehr]

I found the way how to export CardDAV and CalDAV data. So at least this data is not lost...

[justdave]

We had to do something similar about a month and a half ago. We disabled IMAP for everyone before bringing the system back online after the backup restore, and then walked them through copying their cached messages to local storage before enabling them again and copying them back.

[mfehr]

The recovery completed. I did the following:
IMAP: I followed the hint of justdave. The difference is that I changed the status of every user to "Maintenance". After the user saved his data to a local storage, the account was activated again.
CalDAV and CardDAV: I imported the saved ics and csv contact exports according the guidance found at Calendar and Contacts Migration - Zimbra :: Wiki
The interesting learning was that IMAP, CalDAV and CardDAV are mirroring the status of the server and take updates from the IMAP, CalDAV and CardDAV client. - This was demonstrated after I imported all calendar entries in iCal. For a short moment, all imported data was visible. After sync, they were erased again. Importing the ics file on the server did solve solve it.