Note Check the solidDB Release Notes for any limitations that are associated with using a grid in the current release.
A grid configuration consists of configuration parameters and runtime parameters.
Some of the configuration parameters have values that apply to all nodes in the grid and others have values that apply to individual nodes (and can have different values on each node). Most of the configuration parameters can be changed dynamically.
Some of the runtime parameters are persistent and some are volatile. All runtime parameters are kept in memory but persistent runtime parameters are also stored (synchronously) in system tables.
Configuration parameters
Configuration parameters are set up and stored in the [Grid] section of the solidDB server configuration file (solid.ini), see Grid section.
As with standalone solidDB servers, the parameters in the individual nodes can be accessed by using the ADMIN COMMAND 'parameter' command, see PARAMETER. For example, to list all the configuration parameters in the [Grid] section of the solidDB server configuration file (solid.ini), you can run the command:
ADMIN COMMAND 'parameter grid'
In a grid environment, be aware of the following considerations:
▪ Configuration parameter values that affect database behavior should be identical on all nodes in the grid. Differences in these parameters between nodes might lead to unpredictable or even erroneous behavior in the grid.
Parameters that relate to the identification of the server (such as Srv.Name), the network configuration (such as Com.Listen), or server-specific paths (such as Logging.LogDir) can vary for each node.
▪ At startup, each node reads parameters from its own solid.ini, and does not check the parameters in other grid nodes.
▪ If you run the ADMIN COMMAND 'parameter' command on the leader node, by default you set new values for all nodes in the grid.
The leader automatically replicates the change to follower nodes and the new parameter value becomes effective when the majority of the followers have acknowledged the change.
Note The ADMIN COMMAND 'parameter' can display the values from the local node only. To see the values in all nodes, you must make separate connections to run the command locally in each node.
▪ To change a parameter value in the leader node only, you must use the command with the keyword local.For example:
ADMIN COMMAND 'local par general.checkpointinterval=11111';
▪ To change a parameter value in a grid node that is not the leader, you must first establish a direct connection to the node (not a grid connection) and then run the command with the keyword local.
Persistent runtime parameters
The following runtime parameter values are stored in system tables:
▪ List of nodes that are participating in the consensus algorithm and their state, see SYS_GRID_NODES.
Note At any time, not all grid nodes might be participating in the consensus algorithm as the nodes can timeout occasionally.