After the company Zextras released its own builds of Zimbra Collaboration Open-Source Edition 9, many administrators decided to upgrade their mail servers to the new version and contacted Zextras technical support with questions about how to do this without jeopardizing one of the enterprise's key systems.
There are two ways to transition to Zimbra OSE 9 from Zextras. The first, which is the simplest and quickest, is to upgrade Zimbra 8.8.15 OSE on the server to the new version. This approach has two drawbacks. First, you will need a significant technical break to perform the upgrade; second, if something goes wrong, you risk being left without a functioning system and may spend a lot of time trying to get it working again. The second method of transitioning to Zimbra OSE 9 is migrating from a server based on Zimbra OSE 8.8.15 to a server with Zimbra OSE 9. This approach is slightly more complex but does not require a long technical break, and in case of problems on one server, you will always have another server with fully functional Zimbra OSE at hand.
To perform the upgrade, you need to download the Zimbra 9 OSE distribution from the Zextras website and run the installer, which will automatically detect the installed Zimbra OSE 8.8.15 and offer to upgrade the mail server to the new version. The upgrade process is similar to the installation process for Zimbra OSE 9, which is described in detail .
We will examine the migration process using the domain company.ru as an example. Zimbra OSE 8.8.15 runs on the node mail.company.ru, while Zimbra OSE 9 will be installed on the node zimbra9.company.ru. Meanwhile, the MX record in DNS points to the node mail.company.ru. Our task will be to transfer employee accounts from the mail system on the node mail.company.ru to the system deployed on the node zimbra9.company.ru.
The first step towards accomplishing this will be to create a backup on one server and deploy it on another. This task is performed using the Zextras Backup extension, which is part of the Zextras Suite Pro. Please note that to successfully transfer the backup, both servers must have the same version of Zextras Suite Pro installed. Additionally, the minimum version compatible with Zimbra OSE 9 is Zextras Suite Pro 3.1, so do not attempt to transfer data with a version lower than that specified.
To perform the migration, it is recommended to use an external hard drive or a network-attached storage device mounted to the /opt/zimbra/backup/zextras/ directory, which is where the mail server's backup is saved by default. This is done to avoid putting additional load on the operating system while creating the backup.
We will start the migration by disabling the real-time scanning feature on both servers using the command zxsuite backup setProperty ZxBackup_RealTimeScanner false. Then, on the source server, we will start the SmartScan using the command zxsuite backup doSmartScan. This will export all our data to the /opt/zimbra/backup/zextras/ folder, meaning it will be placed on the external storage. After the operation is completed, mount the storage on the target server. Also, if the speed of the internal network allows, the rsync utility can be used to transfer the backup.
After this, you can proceed to deploy the backup on the target infrastructure. This is done using the command zxsuite backup doExternalRestore /opt/zimbra/backup/zextras/. Upon completion of the deployment, you will have a functional copy of the old server, which can be put into operation. To do this, immediately make changes to the MX record of the DNS server and redirect the email flow to the target infrastructure. Additionally, changes must be made to the hostname and DNS record of the node zimbra9.company.ru, so that users accessing the web client can reach Zimbra OSE 9.
However, the work is not yet complete. The fact is that emails received after the backup has finished and before the email flow is switched to the new server are still stored in Zimbra OSE 8.8.15. Therefore, as soon as emails stop arriving at the server with Zimbra OSE 8.8.15, it will be necessary to back it up again. Thanks to Smart scanning, only the data that was missing in the previous backup will be included. Thus, the process of transferring fresh data will not take long.
The same operations can also be performed in the graphical administrator console. The screenshots included in the article sequentially demonstrate the process of creating and importing a backup.
An obvious consequence of this approach to updating the server is that Zimbra users will not have access to some of the received and sent emails for a while; however, they will still be able to receive and send emails normally. Additionally, during the actual restoration of the mailbox content, there may be drops in performance and server responsiveness. Nevertheless, all these nuances are much better than a prolonged technical break and the associated temporary unavailability of the service.
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Source: habr.com
