How to merge two independent ZCS servers into one

Revision as of 02:18, 24 December 2016 by Teodor Vizirov (talk | contribs) (How to merge two independent ZCS servers into ONE)

How to merge two independent ZCS servers into ONE

   KB 23120        Last updated on 2016-12-24  

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This article covers the following:

Case scenario: There are two separate zimbra server, not connected in any way. The aim is to move the data from one of the servers to the other.

The steps below can be used to move a server to another new server too, or to another ZCS server in multi server environment.


Lets call the server that the data will be moved to the "SOURCE", and the server that will move its data to the "source" the "CLIENT". The "source" and the "client" must have the same hostnames prior this operation. The OS versions of the "source" and the "client" can be different. Eg. migrate from centos to ubuntu is ok. The Zimbra versions must be the same, because we will be doing ldap export and import, which doesn't work if the ldap schema is different.

During the steps below, there are couple of scripts to be run. Make sure you make them executable (chmod +x before that. If you are using vim to paste the text, use :set paste before pasting, otherwise when you paste the text the formatting will be gone.


Overview of the steps:

On both servers create base directories for the migration:

# mkdir /migration
# chown zimbra.zimbra /migration

On the old server (CLIENT):

1. Become zimbra

# su - zimbra

2. Backup the data from the "client".

2.1. Backup the domains:

cd /migration
zmprov gad > domains.txt

(open the domains.txt and remove all domains/subdomains that already exists on the "source")

2.2 Backup all admins

cd /migration
zmprov gaaa > admins.txt

2.3 Backup all accounts

cd /migration
zmprov -l gaa > accounts.txt

(open the file accounts.txt and remove the accounts starting with: spam,ham,virus,galsync)

2.4. Add the calendar resources to the accounts file

zmprov gacr >> accounts.txt

2.5 Backup all distribution lists

cd /migration
zmprov gadl > dlist.txt

2.6 Backup all members of the distribution lists

cd /migration
mkdir dl
for i in `cat /migration/dlist.txt`; do zmprov gdlm $i > /migration/dl/$i.txt ;echo "$i"; done

4. Backup all account passwords

cd /migration
mkdir userpass
for i in `cat accounts.txt`; do zmprov  -l ga $i userPassword | grep userPassword: | awk '{ print $2}' > userpass/$i.shadow; done

5. Backup all user,display and given names

cd /migration
mkdir userdata
for i in `cat accounts.txt`; do zmprov ga $i  | grep -i Name: > userdata/$i.txt ; done

6. Backup all accounts data

cd /migration
mkdir accounts
for account in `cat /migration/accounts.txt`; do /opt/zimbra/bin/zmmailbox -z -m $account -t 0 getRestURL "//?fmt=tgz" > accounts/$account.tgz ;  echo $account done; done

7. Backup aliases

cd /migration
mkdir alias
for i in `cat accounts.txt`; do zmprov ga  $i | grep zimbraMailAlias |awk '{print $2}' > alias/$i.txt ;echo $i ;done

Remove the ones that are empty files:

find /migration/alias/* -size 0 | xargs rm -f

8. Backup COS (if different from the "source" server)

If you have only the default COS on the "client", but its with different settings from the COS on the "source" server, you have to rename it and then import it under different name.

Create new entry as follows:

Host: "client" server IP
Port 389 ; Protocol v3
Base DN: cn=zimbra


Level: User + Password
User DN: cn=config
Password is the output from: zmlocalconfig -s ldap_root_password

Click OK.

  • From the left Tree View, expand "cos"
  • Select the COS that you want to export&move to the "source" server
  • From the File menu line above, click on LDIF > Export Subtree > Save on the local disk.
  • Do that with all COS you want to move.

(leave the JXplorer open for the import)

9. Create files for each COS, and their respective user members.

mkdir /migration/cos_users


# The result is a file/s for each COS, and the users within this specific COS
# Note: If there are no custom created COS, there will be no users listed in the default and default_external files. That 
# means all users are in the "default" COS.
# Since the default and the default_external files will contain no users, their respective files are deleted at 
# the end. Zimbra only detect users that are not in the default COS. Thus, every non detected user is in the default COS. 

source ~/bin/zmshutil; zmsetvars

for i in `zmprov gac`
       id=`zmprov gc $i | grep -e "\bzimbraId\b"|cut -d " " -f 2`

       ldapsearch -x -H $ldap_master_url -D $zimbra_ldap_userdn -w $zimbra_ldap_password| grep -e $id -e "dn: uid=" -e mail:|grep -v Email| grep -e zimbraCOSId -B1 -A1|grep mail|awk '{print $2}' > /migration/cos_users/$i

/bin/rm -rf /migration/cos_users/default*


10. Backup Resource/s

The resource backup is the same as the COS explained in point 8 above. The one difference is that you need to specify different "Base DN:" when you login. The Resource is type of a user, and to see the users, we need to use the following bind dn:


As you substitute the above "domain" and "com" with your specific information. The rest is the same as in point 8, as you click on the resource users in order to export them.

11. RSYNC the backed up data to the new server.

rsync -e ssh -axvzKHS  /migration/ root@

The is the IP of the "source" server.

On the new server (SOURCE)

1. Restore COS

To import to the "source" server:

  • Create new entry in the JXplorer as in the import, but this time specify the "source" server IP.
  • Click on the "cos"
  • LDIF > Import File > Select File > Import

Do that with all COS you want to import.

2. Restore Resource/s

Same as restoring COS, except the difference in the binding base dn, explained above in point 10.

3. Recreate all domains

cd /migration
for i in `cat /migration/domains.txt`; do  zmprov cd $i zimbraAuthMech zimbra ;echo $i ;done

4. Create the accounts and set the original passwords

You may have a warning that the resource users are already created, ignore it.

# Creates the users and sets the old passwords. 
# Use dummy password "zimbra" during the user creation

if [ $(whoami) != 'zimbra' ]; then
       echo "Must be zimbra to run $0"
       exit 1;
for i in `cat $USERS`
givenName=$(grep givenName: $USERDDATA/$i.txt | cut -d ":" -f2)
displayName=$(grep displayName: $USERDDATA/$i.txt | cut -d ":" -f2)
shadowpass=$(cat $USERPASS/$i.shadow)
zmprov ca $i zimbra cn "$givenName" displayName "$displayName" givenName "$givenName" 
zmprov ma $i userPassword "$shadowpass"

5. Restore accounts data from the tgz files.

for i in `cat /migration/accounts.txt`; do zmmailbox -z -m $i postRestURL "/?fmt=tgz&resolve=skip" /migration/accounts/$i.tgz ; echo "$i done "; done

6. Add the migrated users from the "client" to their respective COS on the "source"

# The script first list the exported cos names, then iterate through all members within this cos and finally assigns the 
# user to the COS. 

for cos in `/bin/ls -1 /migration/cos_users | tr " " "\n"`
	for i in `cat /migration/cos_users/$cos`
		zmprov sac $i $cos

7. Recreate the distribution lists

for i in `cat dlist.txt`; do zmprov cdl $i ; echo "$i done " ; done

8. Add members to the distribution lists

# add all memebers to each of these distribution lists

if [ $(whoami) != 'zimbra' ]; then
       echo "Must be zimbra to run $0"
       exit 1;
 for i in `cat /migration/dlist.txt`
	for j in `grep -v '#' dl/$i.txt |grep '@'` 
	zmprov adlm $i $j
	echo " $j has been added to list $i"


9. Restore the aliases


if [ $(whoami) != 'zimbra' ]; then
       echo "Must be zimbra to run $0"
       exit 1;
for i in `cat /migration/accounts.txt`
	if [ -f "alias/$i.txt" ]; then
	for j in `grep '@' /migration/alias/$i.txt`
	zmprov aaa $i $j
	echo "$i has alias $j --- Restored"

10. Post steps

  • Shut down the "client" server
  • Fix DNS
  • Confirm your accounts and domains are present and show active, as zimbra run: zmaccts
  • Confirm accounts show mailbox quota usage appropriately: zmprov gqu `zmhostname`
  • Confirm COS shows the correct data: zmprov cta
  • Send emails to test the new users.

Additional Content

Similar articles:


  • Do not depend on the OS. You can migrate from CentOS to Ubuntu. Only requirement is ZCS versions to be same.
  • Does not require running the installation script after the migration
  • Most of the process can be scripted (except the cos/resources section).

Verified Against: Zimbra Collaboration 8.7, 8.6, 8.0 Date Created: 28/09/2016
Article ID: Date Modified: 2016-12-24

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Wiki/KB reviewed by SME1 SME2 COPY EDITOR Last edit by Teodor Vizirov
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