Quorum Server Mode

OceanStor Dorado 6.0.0 HyperMetro Feature Guide

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Quorum Server Mode

In this mode, an independent physical server or VM is used as the quorum server. You are advised to deploy the quorum server at a dedicated quorum site that is in a different fault domain from the two DCs.

In the event of a DC failure or disconnection between the storage systems, each storage system sends an arbitration request to the quorum server, and only the winner continues providing services. The preferred site takes precedence in arbitration.

The following example uses DC A as the preferred site and DC B as the non-preferred site. Table 2-2 describes the arbitration mechanism in quorum server mode.

In the following table, if two or more faults occur in the system, the interval between the faults is less than or equal to 60 seconds.

Table 2-2 Arbitration mechanism in quorum server mode

Fault Diagram	Fault Description	Arbitration Result
	The quorum server malfunctions.	The HyperMetro pair is in the Normal state. The LUNs in both DCs A and B continue providing services. NOTE: HyperMetro automatically switches to static priority mode.
	The link between one storage system (for example, storage system in DC A) and the quorum server is down.	The HyperMetro pair is in the Normal state. The LUNs in both DCs A and B continue providing services.
	A storage system (for example, storage system in DC A) malfunctions.	The HyperMetro pair is in the To be synchronized state. The LUN in DC A stops while the LUN in DC B continues providing services.
	The link between one storage system (for example, storage system in DC A) and the host is down.	The HyperMetro pair is in the Normal state. The LUN in DC B provides services.
	The link between two storage systems is down.	The HyperMetro pair is in the To be synchronized state. The LUN in DC A continues providing services while the LUN in DC B stops.
	A storage system (for example, storage system in DC A) and the quorum server malfunction.	The HyperMetro pair is in the To be synchronized state. The LUN in DC A is inaccessible while the LUN in DC B stops. NOTE: You must forcibly start the HyperMetro pair to enable the LUN in DC B to provide services.
	The link between the two storage systems and the link between a storage system (for example, storage system in DC A) and the quorum server are down.	The HyperMetro pair is in the To be synchronized state. The LUN in DC A stops while the LUN in DC B continues providing services.
	A storage system malfunctions (for example, storage system in DC A) and the link between the other storage system and the quorum server is down.	The HyperMetro pair is in the To be synchronized state. The LUN in DC A is inaccessible while the LUN in DC B stops. NOTE: You must forcibly start the HyperMetro pair to enable the LUN in DC B to provide services.
	The quorum server malfunctions and the link between the host and one storage system (for example, storage system in DC A) is down.	The HyperMetro pair is in the Normal state. The LUN in DC B provides services. NOTE: HyperMetro automatically switches to static priority mode.
	The link between a storage system (for example, storage system in DC A) and the quorum server is down and the link between the storage system and the host is down.	The HyperMetro pair is in the Normal state. The LUN in DC B provides services.
	The link between the storage systems is down and the link between the non-preferred site (for example, DC B) and the host is down.	The HyperMetro pair is in the To be synchronized state. The LUN in DC A continues providing services while the LUN in DC B stops.
	The link between the storage systems is down. Then the links between a storage system (for example, storage system in DC A) and the quorum server as well as the host are down.	The HyperMetro pair is in the To be synchronized state. The HyperMetro services are interrupted. NOTE: To avoid misoperation or data loss, contact Huawei technical support for service recovery.
	One storage system (for example, storage system in DC A) malfunctions and the links between the storage system and the host as well as between the other storage system and the quorum server are down.	The HyperMetro pair is in the To be synchronized state. The LUN in DC A is inaccessible while the LUN in DC B stops. NOTE: You must forcibly start the HyperMetro pair to enable the LUN in DC B to provide services.
	The link between the host and the non-preferred storage system, the replication link, and the link between the quorum server and the non-preferred storage system are down.	The LUN in DC A continues providing services while the LUN in DC B stops.