About Grid Search
Grid search consists of shared files (for example, C:\cluster) and search nodes. When you start up the Search
Service, it looks at the cluster.nodes file in
the shared files location to determine the host, port, and partition
of each node in the cluster. It monitors and communicates the availability
of the search nodes and distributes queries appropriately.
The Search Service also automatically repairs and reconciles search
nodes that are out of sync with the cluster. At startup, nodes will
check their local TID against the current cluster checkpoint and index
queues. If the current node is out-of-date with respect to the rest
of the cluster, it must recover to a sufficiently current transaction
level (at or past the lowest cluster node TID) before servicing requests
for the cluster. Depending upon how far behind the local TID is, this
operation may require retrieval of the last-known-good checkpoint
data in addition to replaying queued index requests.
Although the Search Service performs many actions automatically
to keep your cluster running properly, there are some maintenance
and management tasks you perform manually to ensure quality search
in your portal.
- About CheckpointsA checkpoint is a snapshot of your search cluster that is stored in the cluster folder (for example, C:\bea\alui\cluster), a shared repository available to all nodes in the cluster. When initializing a new cluster node, or recovering from a catastrophic node failure, the last known good checkpoint will provide the initial index data for the node's partition and any transaction data added since the checkpoint was written will be replayed to bring the node up to date with the rest of the cluster.
- About Search Cluster TopologyYour search cluster is made up of one or more partitions, each of which is made up of one or more nodes. As your search collection becomes larger, the collection can be partitioned into smaller pieces to facilitate more efficient access to the data. As the Search Service becomes more heavily utilized, replicas of the existing partitions, in the form of additional nodes, can be used to distribute the load. Additional nodes also provide fault-tolerance; if a node becomes unavailable, queries are automatically issued against the remaining nodes.
- About Search LogsSearch logs are kept for the search cluster as well as for each node in the search cluster. The cluster logs are stored in the \cluster\log folder, for example, C:\bea\alui\cluster\log\cluster.log. The cluster logs include cluster-wide state changes (such as cluster initialization, node failures, and node recoveries), errors, and warnings.
- About the Command Line Admin UtilityThe Command Line Admin Utility lets you to perform the same functions you can perform in the Search Cluster Manager as well as change the run level of the cluster and purge and reset the search collection.
- Purging and Rebuilding the Search CollectionYou can purge and rebuild the contents of the search collection. You might want to do this in a dire situation where the contents of the cluster are corrupted beyond repair and good checkpoints are not available for recovery.
