Cluster Redundancy

If you have multiple clusters on the network, you can configure cluster redundancy to enable APs managed by a particular cluster to failover automatically to another cluster if their parent cluster goes out of service or becomes unavailable.

Active-Standby mode

When an active cluster is inaccessible for APs and external DPs (vSZ-D and SZ100-D) for a while, a standby cluster restores the latest configuration of the Out-Of-Service (OOS) active cluster, then take over all external devices (including AP & external DPs) with AP capacity limited by AP HA licenses on Standby cluster and with services license limits coming from the failed Active cluster. When active cluster is back to in-service state, end-user can "rehome" all APs & external DPs back to the active cluster.

Active-Active mode

When there are multiple clusters, one cluster can be the configuration source cluster, and all other active cluster restores its configuration periodically to make sure the configuration between the clusters are synchronized constantly. When the active cluster becomes inaccessible for APs external DPs (vSZ-D and SZ100-D), they failover to the target active cluster with priority

NOTE
Cluster redundancy is supported only on SZ300 and vSZ-H and failover works only for external DPs (vSZ-D and SZ100-D).

A single standby cluster serves as a failover option for one or many distributed active clusters. Different AAA servers can be configured on active and standby clusters.

Precondition

  • Active-Standby mode

    Active-Standby cluster redundancy can be enabled only when matching the following conditions:
    • All cluster nodes on both the Active and Standby clusters must be in service.
    • System version of both clusters should be the same
    • IP mode should be the same
    • Both clusters should apply same KSPs on all nodes
    • control interface of standby cluster can build connection to which of active cluster

  • Active-Active mode

    Active-Active cluster redundancy can be enabled only when the source active cluster and target active cluster match following conditions:
    • All the cluster nodes must be in service.
    • System version of both clusters should be the same
    • Model (vSZ-H or SZ300) must be the same
    • Network interface number should be equal
    • IP mode should be the same
    • Same KSPs should be applied to all nodes of both clusters
    • "Schedule Configuration Sync" can be enabled only in one cluster.
Configuration

  • Active-Standby mode

    An active cluster can assign only one standby cluster and a standby cluster can monitor up to three active clusters.

  • Active-Active mode

    Each cluster in active-active redundancy can configure up-to three target clusters. "Schedule Configuration Sync" can be enabled only in one cluster.

    It is highly recommended that you update the configuration from the source cluster till it is eventually synchronized.

Cluster status

  • Active-Standby mode

    Active cluster works as a normal cluster and the Standby cluster is in read-only mode. Only a few configurations can be configured on Standby cluster.

  • Active-Active mode

    All clusters work as normal cluster

Configuration backup

  • Active-Standby mode

    Active cluster can backup its configuration and push it to standby cluster periodically if scheduler task is configured.

  • Active-Active mode

    Source active cluster can backup its configuration and push it to target active cluster periodically if scheduler task is configured

Deployment Models

  • Active-Standby mode

    Starting SZ 5.1, following implementations are allowed for Active-Standby mode:
    SZ300 (Active) SZ300 (Standby) LBO and Tunneled WLANs supported
    vSZ-H (Active) vSZ-H (Standby) LBO Only
    vSZ-H/vSZ-D (Active) vSZ-H/vSZ-D (Standby) LBO and Tunneled WLANs supported
    SZ300 (Active) vSZ-H (Standby) LBO Only

    A standby cluster can be reset as a normal cluster if you set-factory after disabling cluster redundancy from active cluster. Once an Active cluster is set to factory default, it can only be made an Active cluster again either by restoring the entire cluster or by enabling cluster redundancy again. Once a Standby cluster is set to factory default, it can only be made as a Standby cluster again either by restoring the cluster or by clicking “Sync Now” on the active cluster. You can still enable the Active-Standby cluster redundancy again from the active cluster, to set Standby cluster after it has been set to factory default.

  • Active-Active mode

    Cluster in active-active mode must be running on either SZ300 or vSZ-H platforms.

License Management
  • Active-Standby mode
    You must manually sync the license on a Standby Cluster after it has been set as Standby cluster by the active cluster. The Standby cluster restores the latest configuration backup files from the Out-Of-Service Active cluster, and leverages the license with the active cluster profile except for the following type of licenses:
    • Permanent AP Licenses
    • Default Temporary AP Licenses
    • Default Temporary AP License Period
    NOTE
    • High-availability (HA) AP licenses must be purchased for Standby cluster. The Standby cluster works only with High-availability (HA) AP licenses and do not sync or accept any regular AP licenses from any source.
    • Active clusters do not accept High-availability (HA) AP licenses—only regular AP licenses must be used.
  • Active-Active mode

    Licenses in each active cluster are independent.

Parent topic: Viewing the System Cluster Overview