Management of data server capacity

If data server capacity does not meet your present or future needs, you can expand its capacity by adding disk space and creating additional containers, or by adding memory. If these simple strategies do not add the capacity you need, also consider adding processors or physical partitions. When you scale your system by changing the environment, be aware of the impact that such a change can have on your database procedures such as loading data, or backing up and restoring databases.

Adding processors

If a single-partition database configuration with a single processor is used to its maximum capacity, you might either add processors or add logical partitions. The advantage of adding processors is greater processing power. In a single-partition database configuration with multiple processors (SMP), processors share memory and storage system resources. All of the processors are in one system, so communication between systems and coordination of tasks between systems does not factor into the workload. Utilities such as load, back up, and restore can take advantage of the additional processors.

Note: Some operating systems can dynamically turn processors on- and offline.
If you add processors, review and modify some database configuration parameters that determine the number of processors used. The following database configuration parameters determine the number of processors used and might need to be updated:
  • Default degree (dft_degree)
  • Maximum degree of parallelism (max_querydegree)
  • Enable intrapartition parallelism (intra_parallel)
You should also evaluate parameters that determine how applications perform parallel processing.

In an environment where TCP/IP is used for communication, review the value for the DB2TCPCONNMGRS registry variable.

Adding additional computers

If you have an existing partitioned database environment, you can increase processing power and data-storage capacity by adding additional computers (either single-processor or multiple-processor) and storage resource to the environment. The memory and storage resources are not shared among computers. This choice provides the advantage of balancing data and user access across storage and computers.

After adding the new computers and storage, you would use the START DATABASE MANAGER command to add new database partition servers to the new computers. A new database partition is created and configured for each database in the instance on each new database partition server that you add. In most situations, you do not need to restart the instance after adding the new database partition servers.