GridCache and PDriver Fault-Tolerance

GridCache supports fault tolerance as described below. Note that Primary and failover Brokers must have their clocks synchronized for GridCache failover.

Because PDriver uses GridCache for its implementation, the same fault-tolerance capability described below applies to PDriver jobs.

Client

If any client puts data in the cache and subsequently fails or logs out, that data is still available to all other clients. This is because the Broker maintains the master index and a complete view of the cached data. This availability does not apply to the local caching mode where a region has a local loader that does not synchronize with the other local caches.

Broker Restart

You can configure GridCache to survive Manager restart and failure. GridCache’s cache index is rebuilt on system startup; objects persisted on the Broker’s file system are recovered. If some or all of the cache is stored in memory, that information is lost.

Failover

A failover Broker can manage a GridServer cache when a regular Broker goes down, if the persistent cache directory is on a shared filesystem. Configure the location of this filesystem from the Manager Configuration page in the GridServer Administration Tool. When the regular Broker goes down and the failover Broker takes over, the failover Broker builds its cache index and begins managing the cache from the shared filesystem. All clients that then fail over to the failover Broker can get references to the existing cache regions on the shared file system.

Note that a failover Broker can be configured to fail over only to one shared cache directory. Therefore, a failover Broker can’t serve as a failover for multiple Brokers with different cache directories; a different failover Broker has to be used for each Broker.

Note that a failover Broker can fail over to only one shared cache directory. One failover Broker can’t serve as a failover for multiple Brokers that have different cache directories. Brokers with different cache directories require separate failover Brokers.