Recovery Options for Shared Nothing Persistence

You can use five policies for the shared nothing persistence as recovery options.

The be.engine.cluster.recovery.distributed.strategy parameter is only supported for the shared nothing persistence. When shared nothing persistence is implemented and recovery is issued, then the policy determines how and when the recovery can be made. The default value of the property is no_data_loss.

Policy Policy Description
no_data Recovers the space without any data. This is same as removing shared nothing persistence files.
data_loss Recovers the space with available data from each seeder. If recovery is done with missing seeders, there is a potential for data loss, because not all members are started, to ensure that all data is recovered. This policy ensures best-effort recovery with the available data.
no_data_loss (Default). Recovers the space only if there are enough members available to recover the data but fast-batch mode replication is not possibel.to be able to recover the previous state of the cluster. Otherwise recovery throws an exception.
fast_load_only Recovers the space only if the no_data_loss conditions are met and replica entries can be distributed among cluster members in fast-batch mode,

When the fast_load_only is used; it is advisable to set 'Cache Agent Quorum' to the total number of cache nodes. This increases the chances of a successful recovery.

robust_load_only Recover the space only if there are enough members to be able to recover the data before shutdown. If enough seeders are not available to recover the previous state of the cluster, recovery throws an exception. This policy forces the slow recovery of the space.
force_load Forces recovery of the space even if the old shared nothing persister files are renamed as per new setup and hostname. This policy bypasses required host, seeder checks and loads the data anyway to complete recovery from old shared nothing files.
Note: (Legacy ActiveSpaces Only) The be.engine.cluster.as.minSeeders property's value is the Cache Agent Quorum value minus the number of backup copies. The seeder information (the current seeder list) is stored in the shared nothing persistence files during shutdown. This information is then used during startup or restart to perform recovery. If cluster is exactly the same during startup (that is, exactly the same members are available and quorum is satisfied), then fast loading of the data is performed.