This article is for administrators who need to restore a Hyper-V SvSAN cluster to a synchronized state after losing or replacing a VSA.
The Challenge: The standard VSA restore functionality is designed for VMware and does not work on Hyper-V.
The Solution: Thanks to SvSAN's lightweight design, the correct approach is simply deploying a new VSA and mirroring the data from the surviving node.
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Resolution/Information
Note: Do not attempt to use the VSA restore method from the WebGUI. Instead, deploy a new VSA and clean up any orphaned targets as explained below.
Table of Contents
- Clean up the old Mirror information from the Surviving VSA.
- Deploy a new VSA as per documentation.
- Confirm Network Performance and enable the Mirror.
- Add the Hosts to the targets on new VSA using iscsicpl tool.
Example Scenario
Cause: A hardware or storage failure on a Hyper-V node results in a lost VSA (or requires an OS reinstall).
Impact: The surviving VSA keeps cluster storage online but operates in a degraded state.
Symptoms: The healthy VSA reports the lost node as Storage Failed or Unsynchronized, similar to the example below:
Goal: To get the SvSAN Cluster back to a synchronized state as quickly as possible.
Steps to synchronize the storage after such failure
Step1
Note: Ensure to contact Support to get the license Key reset of the failed VSA ready for reuse.
Clean up the old Mirror information from the Surviving VSA.
In this example we are going to delete the Remote unsynchronized plex as per
On the WebGUI of the synchronized VSA click on Targets>Storage Information>select the failed VSA
in this case this is the WebGUI of ih-hvsa2 and the storage information for ih-hvsa1.
Then in the next window verify the Plex Information and then Actions>Delete
Confirm DELETE in the next window.
Then under Actions>Demote the target to remove all previous Mirror Information
Then finally System>Actions>VSA Restore
Select the failed VSA and click on Forget.
Confirm when asked. This will clean up any stale information of the failed partner VSA and as the restore feature is not used with Hyper-V it is not required to be kept.
Step2
Once the failed Host is operational again a new VSA can be deployed and the simple target on the Surviving VSA can be mirrored across.
For details on how to deploy the VSA to the Host and for any prerequisites see our Documentation:
Preparing the Host for SvSAN
vsa-deploy-hv
Below are a few screenshots of the process (not exhaustive but main points highlighted)
Ensure to run the StorMagic-Hyper-V Deploy Wizard as administrator
Ensure that credentials with enough permissions to deploy a VM on the server are used - whether domain account or local account.
Accept license agreement and follow import wizard.
Assign storage or choose to Skip storage configuration (pool for the VSA). You can assign later on in Hyper-V this can be assigned later on in VM as for any other VM.
For more information about different type of disk assignments in Hyper-V see:
SvSAN-on-Hyper-V-Identifying-the-different-disks-in-a-typical-deployment
In this example we are assigning a Pass-through disk of 100GB.
Then configure the networking - this can be the same as before but also can be a different IP as there is no information left about the old VSA - whatever is easiest.
Best practice is to use static IPs.
Apply the license (if not already done, contact support asking them to release the license for reuse).
Set the password and the click Finish.
Note: If the deployment fails be sure to check that the correct ports are allowed as in TCP 443 and UDP/TCP 4173.
Step3
Once the VSA has been successfully deployed a quick health check and check of the network performance and then mirror the target from the Surviving VSA to the new VSA.
Network Speed Test
The following article is a good resource for this:
How-to-test-and-validate-network-performance
Discovery
Ensure that the witness is visible on both VSAs - if the new one does not show the same witness as the Surviving VSA then add this manually as per.
How to add a witness to the discovery table of the VSA.
When ready, mirror back the storage from the surviving VSA as per:
How-to-Convert-an-SvSAN-Simple-Target-to-a-Mirrored-Target
Step4
Final step add the hosts to the target/targets on the newly deployed VSA using the iscsicpl tool.
End result there should be an even number of Sessions to both targets showing both hosts as connected.
Drilling to the target under Sessions, the actual IPs that are being used by the hosts is displayed.
See Also
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