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AhsayOBM allows you to back up individual Guest VMs in your Microsoft Hyper-V Host with the MS Exchange Mail Level Backup Set.
The following high level system architecture diagram illustrates the major elements involved in the backup process of a Hyper-V host with AhsayOBM and AhsayCBS.
Refer to this article for the list of hardware requirements for AhsayOBM: Ahsay Hardware Requirement List (HRL) for version 8.1 or above
Refer to this article for the list of compatible operating systems and Hyper-V platforms: Ahsay Software Compatibility List (SCL) for version 8.1 or above
To optimize performance of AhsayOBM on Windows, and to avoid conflict with your antivirus software, refer to the list of processes and directory paths that should be added to all antivirus software white-list / exclusion list.
The latest version of AhsayOBM must be installed on the Hyper-V server. For Hyper-V Cluster environment the latest version of AhsayOBM must be installed on all Cluster nodes.
AhsayOBM user account created on AhsayCBS must have sufficient Hyper-V add-on modules or CPU sockets assigned. Hyper-V Cluster backup sets will require one AhsayOBM license per node.
AhsayOBM user account has sufficient quota assigned to accommodate the storage of the guest virtual machines. (Please contact your backup service provider for details).
Hyper-V guest virtual machines contain three types of virtual disks:
When AhsayOBM backs up a Hyper-V guest virtual machines for an initial or subsequent full backup jobs:
The default Java heap size setting on AhsayOBM is 2048MB, for Hyper-V backups it is highly recommended to increase the Java heap size setting to improve backup and restore performance. (The actual heap size is dependent on amount of free memory available on your Hyper-V server).
Delta generation of large VHD files is a memory intensive process; therefore, it is recommended that the Java heap size to be at least 2048MB - 4096MB. The actual required Java heap size is subject to various factors including files size, delta mode, backup frequency, etc.
Refer to this KB article for how to configure Java heap size on your AhsayOBM.
For stand-alone Hyper-V server, AhsayOBM uses the temporary folder for storing backup set index files and any incremental or differential delta files generated during a backup job. To ensure optimal backup / restore performance, it should be located on a local drive with plenty of free disk space. It should not be on the Windows system C:\ drive.
NOTE For Hyper-V server in Failover Cluster environment, the temporary folder must be set to a network shared path accessible to all cluster nodes, or a Cluster Shared Volume.
AhsayOBM UI must be running when a guest virtual machine is started using Run Direct Restore or when migration process is running.
Make sure NFS service has started for Run Direct to operate. If the backup destination is located on network drive, the logon account must have sufficient permission to access the network resources.
The operating system account for setting up the Hyper-V / Hyper-V Cluster backup set must have administrator permission (e.g. administrative to access the cluster storage).
For Granular Restore, Windows User Account Control (UAC) must be disabled.
For local, mapped drive, or removable drive storage destinations with Run Direct enabled, the compression type will always be set to No Compression and data encryption is disabled to ensure optimal backup and restore performance. The backup set compression type and data encryption settings will only be applied to CBS, SFTP/FTP, or Cloud storage destinations.
For ease of restore it is recommended to back up the whole guest machine (all the virtual disks) rather than individual virtual disks.
The Hyper-V management tools are installed on the server. For Hyper-V Cluster environments Hyper-V management tools is installed on all Cluster nodes.
The Hyper-V services are started on the server. For Hyper-V Cluster environments the Hyper-V services are started on all Cluster nodes.
Example: Windows 2008 R2 Hyper-V
The Microsoft Hyper-V VSS Writer is installed and running on the Hyper-V server and the writer state is Stable. This can be verified by running the vssadmin list writers command.
Example:
C:\Users\Administrator>vssadmin list writers vssadmin 1.1 - Volume Shadow Copy Service administrative command-line tool (C) Copyright 2001-2005 Microsoft Corp. Writer name: 'Task Scheduler Writer' Writer Id: {d61d61c8-d73a-4eee-8cdd-f6f9786b7124} Writer Instance Id: {1bddd48e-5052-49db-9b07-b96f96727e6b} State: [1] Stable Last error: No error Writer name: 'VSS Metadata Store Writer' Writer Id: {75dfb225-e2e4-4d39-9ac9-ffaff65ddf06} Writer Instance Id: {088e7a7d-09a8-4cc6-a609-ad90e75ddc93} State: [1] Stable Last error: No error Writer name: 'Performance Counters Writer' Writer Id: {0bada1de-01a9-4625-8278-69e735f39dd2} Writer Instance Id: {f0086dda-9efc-47c5-8eb6-a944c3d09381} State: [1] Stable Last error: No error Writer name: 'System Writer' Writer Id: {e8132975-6f93-4464-a53e-1050253ae220} Writer Instance Id: {8de7ed2b-8d69-43dd-beec-5bfb79b9691c} State: [1] Stable Last error: No error Writer name: 'SqlServerWriter' Writer Id: {a65faa63-5ea8-4ebc-9dbd-a0c4db26912a} Writer Instance Id: {1f668bf9-38d6-48e8-81c4-2df60a3fab57} State: [1] Stable Last error: No error Writer name: 'ASR Writer' Writer Id: {be000cbe-11fe-4426-9c58-531aa6355fc4} Writer Instance Id: {01499d55-61da-45bc-9a1e-76161065630f} State: [1] Stable Last error: No error Writer name: 'Microsoft Hyper-V VSS Writer' Writer Id: {66841cd4-6ded-4f4b-8f17-fd23f8ddc3de} Writer Instance Id: {a51919e3-0256-4ecf-8530-2f600de6ea68} State: [1] Stable Last error: No error Writer name: 'COM+ REGDB Writer' Writer Id: {542da469-d3e1-473c-9f4f-7847f01fc64f} Writer Instance Id: {7303813b-b22e-4967-87a3-4c6a42f861c4} State: [1] Stable Last error: No error Writer name: 'Shadow Copy Optimization Writer' Writer Id: {4dc3bdd4-ab48-4d07-adb0-3bee2926fd7f} Writer Instance Id: {d3199397-ec58-4e57-ad04-e0df345b5e68} State: [1] Stable Last error: No error Writer name: 'Registry Writer' Writer Id: {afbab4a2-367d-4d15-a586-71dbb18f8485} Writer Instance Id: {25428453-2ded-4204-800f-e87204f2508a} State: [1] Stable Last error: No error Writer name: 'BITS Writer' Writer Id: {4969d978-be47-48b0-b100-f328f07ac1e0} Writer Instance Id: {78fa3f1e-d706-4982-a826-32523ec9a305} State: [1] Stable Last error: No error Writer name: 'WMI Writer' Writer Id: {a6ad56c2-b509-4e6c-bb19-49d8f43532f0} Writer Instance Id: {3efcf721-d590-4e50-9a37-845939ca51e0} State: [1] Stable Last error: No error
# lsmod | grep hv hv_netvsc 23667 0 hv_utils 7012 0 hv_storvsc 10022 2 hv_vmbus 91567 4 hv_netvsc,hv_utils,hid_hyperv,hv_storvsc # ps -ef|grep hv root 267 2 0 18:07 ? 00:00:00 [hv_vmbus_con/0] root 268 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 269 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 270 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 271 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 272 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 273 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 274 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 275 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 276 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 277 2 0 18:07 ? 00:00:00 [hv_vmbus_ctl/0] root 1174 1 0 18:07 ? 00:00:00 /usr/sbin/hv_kvp_daemon root 1185 1 0 18:07 ? 00:00:00 /usr/sbin/hv_vss_daemon root 1332 1316 0 18:11 pts/0 00:00:00 grep hv
For Hyper-V 2008 R2 server in order to use Run Direct restore feature the “Microsoft Security Advisory 3033929” security update must be installed.
Please refer to the following KB article from Microsoft for further details: https://support.microsoft.com/en-us/kb/3033929
For Run Direct Hyper-V Cluster backup sets the storage destination must be accessible by all Hyper-V nodes.
For Hyper-V Cluster backup sets the guest virtual machines must be created and managed by the Failover Cluster Manager.
AhsayOBM v8 supports two methods for Hyper-V guest VM backup, VM Snapshot and Saved State.
The VM snapshot method is the preferred backup option, as it supports live guest VM backups. This means guest VM will not be put into a saved state when a VSS snapshot is taken during a backup job. So it will not affect the availability of any applications or services running on the guest VM every time a backup job is performed.
If the VM Snapshot method cannot be used, AhsayOBM will automatically use the Saved State method.
Requirements 1. The guest VM must be running.
2. Integration services must be enabled on the guest VM.
3. The Hyper-V Volume Shadow Copy Requestor service is running on the guest VM installed with Windows operating system. Please refer to the following article for further details: https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/reference/integration-services#hyper-v-volume-shadow-copy-requestor
4. For guest VMs installed with Linux / FreeBSD operating systems, the VSS Snapshot daemon is required for live backups, not all Linux / FreeBSD versions support live backup on Hyper-V. For example, only FreeBSD 11.1 supports live backup while for Ubuntu, version 14.04 LTS to 17.04 LTS supports live backups. Please refer to the following article for further details: https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/supported-linux-and-freebsd-virtual-machines-for-hyper-v-on-windows
5. The guest VM volumes must use a file system which supports the use of VSS snapshots, for example NTFS.
6. The guest VMs snapshot file location must be set to the same volume in the Hyper-V host as the VHD file(s).
7. The guest VM volumes have to reside on basic disks. Dynamic disks cannot be used within the guest VM.
Some older Windows operating systems installed on guest VM's which do not support either Integration Services or the Hyper-V Volume Shadow Copy Requestor Service, will not support VM snapshot method, for example, Microsoft Windows 2000, Windows XP, or older Linux/FreeBSD versions.
If any of the VM Snapshot method requirements cannot be fulfilled, AhsayOBM will automatically use the Save State method. When the Saved State method is used, the guest VM is placed into a saved state while the VSS snapshot is created (effectively shut down), and the duration is dependent on the size of VM and performance of Hyper-V host. The downside is it may affect the availability of any applications or services running on the guest VM every time a backup job is performed.
CBT Cluster Services (Ahsay Online Backup Manager) is installed and enabled upon installation / upgrade to version AhsayOBM v8.1.0.0 or above.
1. CBT (Changed Block Tracking) is used to optimize incremental backups of virtual machines by keeping a log of the blocks of data that have changed since the previous snapshot making incremental backups much faster. When AhsayOBM performs a backup, CBT feature can request transmissions of only the blocks that changed since the last backup, or the blocks in use.
CBT service is supported on all the backup destinations for AhsayOBM.
2. CBT cluster service is only installed on Windows x64 machine.
3. Check if CBTFilter is enabled.
Example:
i. This can be verified by running the net start CBTFilter command.
C:\Users\Administrator>net start CBTFilter The requested service has already been started. More help is available by typing NET HELPMSG 2182.
ii. Note: For Windows Server 2008 R2, if the following error is displayed
C:\Users\Administrator>net start CBTFilter System error 577 has occurred. Windows cannot verify the digital signature for this file. A recent hardware or software change might have installed a file that is signed incorrect or damaged, or that might be malicious software from an unknown source.
The issue may be related to the availability of SHA-2 code signing support for Windows Server 2008 R2 (https://technet.microsoft.com/en-us/library/security/3033929).
To resolve the issue, install the following patch from Microsoft https://www.microsoft.com/en-us/download/confirmation.aspx?id=46083
Restart the affected server afterward for AhsayOBM to operate properly.
4. CBT Cluster Service and CBTFilter will NOT be installed on Windows Server 2016 where a built-in system called Resilient Change Tracking (RCT) will be used instead. For details of RCT, please refer to Windows Server 2016 and 2019 RCT Requirement.
1. AhsayOBM would not install CBT Cluster Services (Ahsay Online Backup Manager) but use the native built-in RCT (Resilient Change Tracking) feature of Windows server 2016 and 2019 instead.
2. The guest virtual machine version in Hyper-V must be 8.0 or above.
Example:
i. This can be verified by using Windows PowerShell.
get–VM | format–table name, version
ii. If the version is not 8.0 or above, then need to upgrade the virtual machine configuration version.
Update-VMversion <vmname>
Please refer to the following link of Microsoft for details about virtual machine version: https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/deploy/Upgrade-virtual-machine-version-in-Hyper-V-on-Windows-or-Windows-Server
To get full use of Hyper-V, install the appropriate linux-tools and linux-cloud-tools packages to install tools and daemons, e.g. VSS Snapshot Daemon, for use with virtual machines. Please refer to the following link for the details of requirements for Ubuntu relating to Hyper-V daemons: https://docs.microsoft.com/en-us/windows-server/virtualization/hyper-v/supported-ubuntu-virtual-machines-on-hyper-v
1. Backup of guest machines located on a SMB 3.0 shares is not supported.
2. Backup of virtual machine with pass through disk (directly attached physical disk) is not supported.
3. For backup of individual virtual disks, the restored virtual machine does not support the reversion of previous snapshots, if the snapshot contains disks which are not previously backed up by AhsayOBM.
4. A guest virtual machine can only be restored to the Hyper-V server with the same version, e.g. backup of a guest on Hyper-V 2012 R2 server cannot be restored to Hyper-V 2008 R2 Server or vice versa.
5. The guest virtual machine will not start up if the virtual disk containing the guest operating system is not restored.
6. Run Direct Restore of VM containing .VHDS shared virtual disk(s) is not supported.
7. Restore of individual virtual disks is only supported using the Restore raw file option for a virtual disk with no snapshots.
This will require modification of Hyper-V guest configuration files, and this only should be done if you have in-depth knowledge and understanding of Hyper-V, otherwise the guest virtual machine may not startup properly.
8. Replication must be disabled for the VM selected for backup, otherwise there may be following error occurring during backup job:
Failed to backup virtual machine "guest_guid"., Reason = "Failed to take VM snapshot. Error = [CreateVirtualSystemSnapshotV2] Error="The method call failed." (32775)".
Refer to here for more details.