SIRIS, ALTO, and NAS: Best practices for Local Virtualizations



This article provides best-practices for balancing local virtualization performance with the Datto appliance's other tasks and functions. 


  • Datto SIRIS


Perform Local Virtualization Tests

We DO NOT support a local virtualization test bridged to the live network. This will put you in a live disaster recovery scenario as any data change made to the virtualization on the Datto appliance will NOT be written to the live server.

Performing a local virtualization test helps you to be better prepared in the event of a disaster recovery scenario. Testing allows you to determine how long it might take to boot a virtualization, and identify issues that might not be present in screenshot verification.

Local virtualization tests also help determine the proper resources to assign to VMs.

Allocate Resources Efficiently

It might be tempting to assign a large number of CPUs and RAM to a VM to match the production system. But remember that your Datto appliance is doing more than just running the VM. Allocating too many resources to the VM can degrade the performance of the device's core functions, and can cause it to become unstable.

You can see the Datto device’s total CPU and RAM availability on the Local Virtualization Options screen of the GUI.

Consider ESXi Virtualization

If you have a hypervisor, ESXi virtualization can leverage its system resources to virtualize a restore, and use the Datto appliance as a datastore, removing significant load from your SIRIS.

Pause Offsite Sync

Offsite sync processes can be CPU-intensive. Pausing them will remove the overhead of preparing and sending data offsite, helping to keep the device stable.

Reduce Concurrent Backup Settings

Too many backups running simultaneously can destabilize the device. You can temporarily reduce the number of concurrent backups to lower system load.

Avoid Unnecessary Tasks

Secondary tasks, like running a backup report or a RoundTrip, can cause system load. Consider waiting until you no longer need the local VM before starting them.

Pause Screenshots

The screenshot process creates local VMs, which consume resources. During a disaster recovery scenario, you can disable them in the GUI at Configure → Device Settings → Disable Screenshots.

Restore the Production Machine Quickly

Datto appliances are designed for short-term business continuity use during disaster recovery. They are not intended as a long-term hypervisor solution.

Minimizing downtime on the production machine will help to ensure that recovery is successful.

Avoid Unnecessary Reboots

Datto appliances are for short-term business continuity use during disaster recovery. They are not intended as a long-term hypervisor solution.

Minimizing downtime on the production machine will help to ensure that recovery is successful.

Frequently-Asked Questions

Can we push 4K resolution from virtualizations?
The Datto appliance is not capable of driving 4K resolution. 

Our server requires a USB hardware key to use; is there any way to use it with the Datto appliance?
USB passthrough is supported; however, Datto cannot guarantee compatibility with all brands of USB devices. See the following articles for more information about enabling this feature (external links):

What is the minimum free space required to run a virtualization on Datto physical appliances and Datto virtual appliances?
The amount of free space needed on the Datto appliance depends on the amount of data change that you anticipate the VM will create while it is running.

Overall you will need 15-20% above the amount of space needed for snapshots of the Virtual Machine while maintaining a stable VM and device.

Datto appliances require a minimum of 1 GB above any data change you expect to happen during the time that the virtualization is running. However, at this threshold, ZFS performance will drop.

Servers that generally create larger amounts of data change (file servers, Exchange Databases, or SQL Databases) will need more free space (closer to 20%) on the Datto device.

You may also need additional free space on the device if there are other agents paired. These agents will need space to continue backing up, and building transfer files to be sent offsite.

Datto recommends maintaining at least 25 GB of free space above the virtualization's expected data change for best performance.

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