Flexible Security

Vembu BDR Suite [1] helps you back up Hyper-V and VMware ESXi environments with up to 10 virtual machines (VMs) free of charge. In this article, I back up a Hyper-V host and start by installing an agent for the connection – the Vembu integration service (VIS) – that is also capable of backing up server-based services such as Exchange or SQL Server on the VMs.

You do not need to install any additional software on the virtual machines themselves. In addition to standalone Hyper-V hosts, you can also back up clusters with Vembu. For the backup, the vendor draws on the Hyper-V volume shadow copy service (VSS). The VMs are therefore included in the backup, instead of just copying the virtual hard drives and their data.

Vembu BDR Suite also relies on resilient change tracking (RCT) in Windows Server 2016 and 2019, a feature that allows backup software to detect which data has changed on the virtual disks since the last full backup so that only the changed data is saved. In this case, the virtual hard drive consists of blocks. If you perform a full backup, all blocks are backed up to a repository.

However, for the next backup, you will only want to back up the changed blocks. The change block tracker creates a bitmap of all the blocks on the virtual hard drive. As soon as the data in a block changes, it is marked accordingly. At the time of a backup, the backup software only needs to check the bitmap for all blocks that have changed since the last backup and then simply backs up the changed blocks.

This method has been possible without additional functions since Windows Server 2016 with RCT. RCT creates three bitmaps: one in memory and two on the hard disk, which ensures that the bitmaps are not lost. As long as the VM is running, the backup software checks the bitmap and only backs up the changed blocks when an incremental backup is requested. If a VM is migrated or a power failure occurs, the backup software still has two bitmap files from which to choose.

The RCT file is used during normal operation. In case of a sudden power failure or a similarly serious event, the modified region table (MRT) file can also help. This table is maintained in write-through mode and has coarser tracking granularity. In the event of a sudden power failure, the MRT file still provides a record of what has changed on the disk and guides the back up of data on recovery. The technology thus accelerates and simplifies incremental backups.

Functions and Limitations

Backups are easy to perform with the features included in the free edition of Vembu BDR Suite. As mentioned, the free version supports VMware ESXi and Hyper-V; you can also connect to vCenter with the free version. Up to 10 VMs are supported, and 10 EC2 instances can be backed up in Amazon Web Services (AWS). The same applies to services in Microsoft 365 and Google G Suite. The limit is 10 user accounts and their data. Backups of conventional Windows servers are also possible, as well as up to 10 workstations. You can also include Mac computers in addition to your Windows computers.

You can back up the VMs on Hyper-V hosts to local disks; CSV files, SMB shares, and Storage Spaces Direct are also supported. The free version is already capable of backing up applications in the VMs, including Exchange Server and SQL Server, among others, and can perform the backups online and delete transaction logs.

If you are satisfied with the product overall but need to back up more than 10 VMs, you can opt for one of the commercial editions. The costs are from $108 per CPU socket for the Standard Essentials edition to $360 for the Enterprise edition. The VMs to be backed up also need to be licensed. The prices are $18 for the Standard Essentials edition and $60 for the Enterprise edition.

Installing Vembu BDR Suite

The suite does not need to be installed on the Hyper-V host itself; instead, the connection and backup take place over the network. After the install, the functions of the Enterprise Edition can initially be used for 30 days, after which the software switches to Free mode. Free mode can also be enabled at any time beforehand; the settings for the editions can be found under Management | BDR Edition, which is where you can activate the functions of the Free Edition immediately after the install, as well the functions of the other editions, provided you have licensed the product.

The Vembu BDR Suite management data end up in a PostgreSQL database that's installed on a backup server when the suite is installed and does not contain the data of the virtual hard drives themselves, only the information of the backup for recovery and management. During the install, you specify the web console port and the back support. The installation wizard displays the default data in the window. You can also specify the username for accessing the administration interface and the corresponding password during the installation.

After you select from the various options, the wizard starts the installation. Afterward, you need to check in system services management whether the VembuBDR system service is running and whether the user account is correct. Parallel to the web interface, BDR also offers the Vembu agent interface on the server. From the context menu of the icon, you can restart the system service if necessary. The agent also displays messages telling you whether backups completed successfully or terminated with errors. These messages can also be disabled in the context menu.

To connect Hyper-V hosts, you need to start the VembuBDR system service with a domain account that is authorized to install an agent and perform tasks on the Hyper-V hosts. If the authorization is not sufficient, the wizard for connecting a new Hyper-V host will report an error to match.

Connecting the Hyper-V Host

Once the system service is started, you can open the web interface and log in with the user account you specified during installation. To back up Hyper-V hosts, first go to Backup | Configure Backups | Microsoft Hyper-V, which is where you add the servers that have the VMs you want to back up.

When adding Hyper-V hosts, use the Add Hyper-V Servers or Add-Hyper-V Clusters side tab to select the type of host you want to connect to (Figure 1). In the following, I assume you are setting up a standalone Hyper-V host because in most cases clusters have more than 10 VMs.

In the upper field, enter the name of the Hyper-V host. For Add Credentials, enter the credentials for accessing the Hyper-V host. For Hyper-V backup, an agent must be installed on the host (see the "Access Authorizations as a Source of Error" box). The various logins can be managed at any time under Infrastructure | Credentials. The item Management | BDR Clients | List Client Agents lets you view the currently connected servers, including the version of the client, in the course of connecting the host. You have to confirm the install agent prompt to connect the Hyper-V host.

Backing up Hyper-V

Once the host is connected, you can configure the backup with the Configure Backup button. However, you first need to define a repository to which the VM data will be backed up by selecting Infrastructure | Backup Repository | Create New Backup Repository (Figure 2). Besides local data carriers, network shares can be used.

Of course, you can also create multiple backup targets, which you define later in the backup jobs. Under Infrastructure | Backup Repository you can view the individual targets, as well as the free storage space. Once you have created at least one backup repository, use Configure Backup to create a backup job for the individual Hyper-V hosts that are connected to Vembu. When using the free version, you can choose whether you want to use all backup features for a maximum of 10 VMs or whether limited features are sufficient for more VMs. With the limited features, only full backups are created, and you have to delete the backups manually. Retention is disabled in the free version when you back up VMs with the standard features.

On the first page of the wizard (VM Selection), you select the VMs to be backed up. You can see which VMs are running or currently switched off. Use the VM | Disk Exclusion button to remove individual virtual disks from the backup jobs. By default, Vembu BDR backs up all virtual disks from all selected VMs.

Under Guest Processing, you can also back up the applications on the VMs by activating Guest Processing Settings. In this way, you can, for example, create an online backup of Exchange Server and your SQL databases. The software can delete the transaction logs after the backup if required, but first you need to enter the credentials for accessing the virtual server applications on the configuration page. If you already used these credentials when connecting the Hyper-V hosts and the user account is the same, you can select it directly from the menu.

Next, you need to decide when the servers will be backed up from the numerous options. Daily and weekly backups are possible, as are multiple daily backups. You can also specify that full backups always take place at certain times and how many full backups Vembu will keep in the repository at the same time.

The Settings item lets you define when the backups will expire and be deleted from the repository. Additionally, multiple incremental backups can be grouped by specific time periods, which will significantly reduce the number of restore points. Finally, you can select the backup repository and enable encryption. The last step is to display a summary of the individual entries and give the backup job a name. By default, the backup is started immediately after saving, but this can also be disabled. If you click on the status of a backup, you will see the details of the current operation.

Managing and Monitoring Backups

In the web interface, you can see a summary of the currently active and processed jobs on the dashboard (Figure 3). Backup | List Backup Jobs shows all the defined backup jobs and the current status of the backup. If a backup is running, the list of backup jobs displays here. This is also where you suspend and resume jobs. If necessary, you can cancel running backup jobs from the Status item.

Under Reports, you can see descriptions of the latest job runs and whether the backups were successful. The volume of data for the job and possible errors, warnings, and other information can also be found here. Click on a job to view more detailed information, including the VMs to be backed up, the excluded disks, the schedule, the sequence of backups, and the disk encryption configuration.

If data is lost, you can restore VMs and individual data from the VMs from the Recovery menu item. To do this, select the icon for recovery and then specify whether you want to recover a complete VM or individual servers. When you start the recovery process, you have numerous options to choose from, including an instant recovery process, a full recovery, individual data, and even an image. Once the wizard is done, follow the prompt, and recovery will begin with the specified options. Again, clicking on Status will give you more detailed information.

Conclusions

Vembu BDR Suite is quite an interesting piece of software for companies that want to back up VMs – up to 10 for free. Because the free version also supports backing up conventional servers, it lends itself to flexible use. Vembu BDR Suite is easy to manage in the web interface, and anyone who needs more than the features of the free edition can easily switch to a larger, commercial version by purchasing a license, with no need to reinstall; the backup data and settings are also transferred.

If you do not use Hyper-V on your network, you can also back up VMware ESXi. The procedure is identical, and the interface is the same. Only the approach for connecting the hosts is slightly different. In the same interface, you can also back up conventional Windows servers, as well as data in the cloud – also free of charge.