Clients access the block storage resources in the storage cluster through iSCSI.
iSCSI HA management allows you to set an HA VIP for the storage front-end network that provides storage service for the storage cluster to ensure service continuity. The clients can discover the block devices in the storage cluster by accessing the iSCSI HA VIP, without being affected by storage node failure.
To improve the availability of a block storage service, assign the storage nodes for that service to an iSCSI HA group, which is accessible at a virtual IP address (VIP). Each iSCSI HA group contains one primary node and multiple backup nodes. When the primary node fails, one of the backup nodes will take over to provide block storage network access.
Load balancing dynamically distributes service requests across multiple block service nodes.
After you enable load balancing, the primary node looks up the load balancing weight table and selects an optimal node when it receives a service request destined for the VIP.
If the primary node is the optimal node, the client establishes a service connection to the primary node.
If the primary node is not the optimal node, it sends the IP address of the optimal node to the client. Then, the client establishes a service connection to the optimal node.
To use load balancing, you must first create an iSCSI HA group.
iSCSI HA group management includes the following topics:
Manage iSCSI HA groups—Enable, disable, edit, and delete iSCSI HA groups.