Best Practices and Recommendations

Please consider the following recommendations:

• Use the latest version of AhsayOBM (v9.1 or above).

  Install the latest version of AhsayOBM on the staging machine or Backup Client Computer for backup of VM hosted on a VMware ESXi server, or on a Windows vCenter server.

  Always stay up to date when a newer version of AhsayOBM is released. To get our latest product and company news through email, please subscribe to our Ahsay Newsletter:

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• Install AhsayOBM on a physical staging machine

  For best backup and restore performance, it is highly recommended that AhsayOBM is installed on a server grade staging machine or backup client computer with sufficient memory and processing power. As guest VM can be very large, during backups and restore this may involve the compression & encryption of large amounts of data, which can be very resource intensive.

• VMware Tools

  Make sure the latest version of VMware Tools is installed on each guest VM selected for backup. VMware Tools is used by AhsayOBM to quiesce the guest VMs prior to backing them up to create consistent backup for your VMs.

  Quiescing is a process that ensures that the disk data is in a state suitable for backups to reduce the possibility of data corruption upon restore. This is especially important for transaction-based applications running on VMs like MS SQL Server, MS Exchange etc. There are different types of quiescing mechanisms, according to the guest operating systems (e.g. Crash-consistent, File-system-consistent and Application-consistent quiescing).

• Do not use a guest VM as a staging machine

  Although installing AhsayOBM on a guest VM as a staging machine is possible, the backup and restore will work as on a physical staging machine. This setup is actually inefficient and can lead to possible performance bottlenecks on the VMware host server, as in a VMware host the virtualization layer separates guest VM OS layer and the VMware host physical hardware layer.

  As the guest VM operating system does not have direct access to physical hardware where the data resides, a backup agent installed inside the guest VM must go through the virtualization layer to access the guest virtual machine data.

• Use the VDDK backup mode / CBT feature

  The CBT (Change Block Tracking) feature, which is required for backup in VDDK mode, is supported by VM host with VMware Essentials License (or other paid licenses). The CBT feature, which is utilized for tracking changes of data blocks since the last backup can be done quickly and directly on the VM host. Therefore, the performance of incremental backups is much faster with VDDK backup mode.

  Another advantage of VDDK mode is the amount of data backed up is relatively smaller. The used data size of the guest VM is backed up instead of the provisioned size, so the storage cost of these backups will be less.

• The temporary directory of a VMware VM backup set is set to a local volume, and not to a network volume (e.g. to improve I/O performance).

  However, the temporary directory should not be set to the system volume (e.g. where the operating system is installed).

  It is highly recommended to set the temporary directory folder to another location with sufficient free disk space other than Drive C: (e.g. Drive E:).

• Plan your backup schedules carefully to minimize any performance impact on the VMware host.

  To avoid concentrated disk, I/O on the VMware host datastores which will have a negative performance impact on the guest VMs residing on these datastores, you should schedule your backups to limit the number of concurrent VM backups on a host and shared datastores. Hosts typically share the same datastores in virtual environments, and bottlenecks caused by too many simultaneous VM backups on a single datastore will affect all hosts that have VMs running on that datastore.

• Backup the guest VMs to more than one destination

  To provide maximum data protection and recovery flexibility, you should consider storing your guest VM backups in multiple backup destinations, ideally both onsite and offsite locations. Onsite locations on local or network drives will enable very quick recovery even for large guest VMs. While offsite locations will ensure that if there is a site outage, the guest VM can be restored from another location.

• Consider increasing the Java memory allocation setting for AhsayOBM (Java heap space) as more memory is required for in-file delta generation, which is performed by AhsayOBM, depending on the provisioned size of the guest VMs. A relatively large Java heap size may be required, i.e. 4GB, 6GB, 8GB etc.

  If you are using Granular restore, it is recommended to increase the Java heap size space to at least 4GB or above for optimal performance.

  Refer to this link for more details about the modification of the java heap size setting for AhsayOBM:

  FAQ: How to modify the Java heap size setting of AhsayOBM / AhsayACB.

• It is highly recommended to back up the whole VM instead of individual disk for backup of virtual machine with snapshot.
• Consider performing routine recovery test to ensure your backup is setup and performed properly.
• Consider disabling the memory snapshot or quiesce guest options when taking snapshot for VMware VM backup, to shorten the time required for the process.
  • Snapshot the virtual machine's memory
  • QUiesce guest file system (Needs VMware Tools installed)
• For backups using vCenter Server Appliance (vCSA) on VMware ESXi server, a separate Backup Client Computer must be prepared for the AhsayOBM to be installed on, which can connect to the vCenter Server Appliance (vCSA) through a LAN.

• Periodic Backup Schedule

  The periodic backup schedule should be reviewed regularly to ensure that the interval is sufficient to handle the data volume on the machine. Over time, data usage pattern may change on a production server, i.e. the number of new files created, the number of files which are updated/deleted, and new users may be added etc.

  Consider the following key points to efficiently handle backup sets with periodic backup schedule.

  • Hardware - to achieve optimal performance, compatible hardware requirements is a must. Ensure you have the backup machine’s appropriate hardware specifications to accommodate frequency of backups,
    • so that the data is always backed up within the periodic backup interval
    • so that the backup frequency does not affect the performance of the production server
  • Network - make sure to have enough network bandwidth to accommodate the volume of data within the backup interval.
  • Retention Policy - also make sure to consider the Retention Policy settings and Retention Area storage management which can grow because of the changes in the backup data for each backup job.