HA Policy Basic Operations

If you wish to fully understand the basic high availability policy functions of the ZSvirt platform, you can follow these steps:

1. Enable HA Policy
2. Set VM Failover Strategy
3. Set Host Error Detection
4. Set Advanced Settings
5. View High Availability Logs
6. Disable HA Policy

Enable HA Policy

High availability policies in ZSvirt are enabled by default. If they have been disabled, you can click on the Menu > Business Reliability > HA Policy, and then turn on the switch at the top of the HA Policy page to enable the high availability policies.

Set VM Failover Strategy

After enabling the high availability policies, you can set the high availability migration strategies for the four typical fault scenarios on the Migration Policies page:

Typical Scenario	Management Network Connection Status	Storage Network Connection Status	Business NIC Status	Migrate on Failure?	Migration Explanation
Scenario A	Normal	Normal	Failure	Migrate | Do Not Migrate	Supports setting to migrate or do not migrate.
Scenario B	Normal	Failure	Normal	Migrate | Do Not Migrate	Supports setting to migrate or do not migrate. However, in a SAN storage environment, if set to do not migrate here, the storage network connection status failure will still trigger automatic migration.
Scenario C	Normal	Failure	Failure	Migrate | Do Not Migrate	The migration strategy for when both the storage connection status and the business network card status fail follows the migration strategy for either status failing: - If the migration strategy for both the storage connection status and business network card status failure scenarios is set to do not migrate, then this is set to do not migrate. If the migration strategy for one of the failure scenarios is set to migrate, then this is set to migrate.
Scenario D	Failure	Normal	Normal	Do Not Migrate	When the management network status is faulty, it is not supported to set a fault migration strategy.

Set Host Error Detection

After enabling the high availability policies, you can set the host failure judgment policies on the Migration Policies page:

Host Error Detection Item	Description
Host Self-Inspection Interval	The interval that a host inspects its own status. Default: 5. Unit: second.
Maximum Host Self-Inspection Attempts	The maximum number of attempts that a host inspects its own status. If the self-inspection of a host fails by the maximum attempts, it is determined that network errors occur with the host. Default: 6.

Set Advanced Settings

After enabling the high availability policies, you can set the advanced settings for high availability policies on the Advanced Settings page, including advanced settings for both virtual machines and hosts.

Category	Name	Description
Virtual Machine	HA VM State Update Speed	The speed of updating the state of NeverStop virtual machines on the UI. Default: 1. Valid values: -1 to 5. A higher value indicates a lower update speed. However, a lower update speed makes the system ignore a lot of outdated notifications, thus decreasing the system workload. If set to -1, the NeverStop VM states on the UI are not updated automatically.
	Maximum Interval for VM Attempt to HA Start	The maximum interval for the system to finish the GC (garbage collection) job and attempt to restart a NeverStop VM according to the HA policy after the virtual machine is stopped unexpectedly. Default: 300. Unit: second.
	VM Retry HA Start Inverval	The interval for a Neverstop VM to retry an HA start after the previous HA start attempt fails. Default: 60. Unit: second.
	HA VM State Scanning Interval	The interval to scan the status of a NeverStop VM after it fails to HA start. Default: 60. Unit: second.
Host	Timeout Period for Host Connecting to Data Storage	The time for hosts to attempt to connect to data storage. If a host fails to connect to a data storage during this period, its connection attempt is determined as timeout. Default: 5. Unit: second.
	Abnormal Host Status Update Interval	The interval for the system to check and update the status of abnormal hosts. Default: 5. Unit: second.
	Minimum Connection Attempts Required to Determine Host is Disconnected	The maximum times for the system to attempt to connect to a host. If the system fails to connect to the host after the specified times of attempt, the host is determined as disconnected. Default: 12.
	Ping Response Time to Determine Host Connection is Established Successfully	The time period for the system to wait the host response after it pings the host. Receiving a response within this period indicates that the system establishes a successful connection with the host. Default: 5. Unit: second.
	Minimum Connection Success Rate to Determine Host is Re-Connected	The minimum rate of successful connections occupied in total connection attempts to determine a disconnected host is successfully re-connected. Default: 50. Unit: %.
	Minimum Successful Connections Required to Determine Host is Re-Connected	The minimum successful connections that the system has to establish with a disconnected host before the host can be determined as re-connected. Default: 5.

View High Availability Logs

After enabling the high availability policy, if the platform triggers the high availability mechanism, high availability logs will be generated. You can view these logs on the O&M Management > Tasks > HA Task page. The logs support viewing task results, virtual machine names, virtual machine owners, previous hosts, target hosts, start times, and completion times, enriching operational scenarios for auditing and tracing.

• Supports selecting a time period to view high availability logs for virtual machines during the selected period. Available time periods include: last 7 days, last month. By default, the latest 7 days of logs are displayed.
• Supports custom time periods to view high availability logs for virtual machines during the set period.
• Supports searching for high availability logs for virtual machines by entering the virtual machine name or owner.
• Supports filtering high availability logs for virtual machines by task result. Task results include: success, failure.
• Supports sorting high availability logs for virtual machines by start/completion time.
• Supports exporting high availability logs for virtual machines in CSV format.
• Supports adjusting the number of completed high availability logs for virtual machines displayed per page. Selectable values are: 10, 20, 50, 100, and pagination is supported.

Disable HA Policy

If you wish to globally disable the high availability feature for virtual machines, you can do so on the HA Policy page by clicking the Disable action.