To ensure no interaction between Optimizer and TimeFinder, the customer can take one of the following steps.
Solution 1: Exclude all the standard volumes that will be involved with TimeFinder so the Optimizer can not swap them. This is done by marking the logical volume attributes for this set of volumes to no swap. This will eliminate all the interaction scenarios. Optimizer will swap the remaining volumes to get to an optimal configuration in the Symmetrix system. This may prevent Optimizer from providing the best- performing configuration.
This is recommended when TimeFinder’s usage is limited to a set number of volumes or is not controlled by scripts.
Solution 2: Separate the TimeFinder activity from the Optimizer activity. Scripts or jobs controlling the TimeFinder activity should be set to complete prior to Optimizer’s swap time zone. Additionally, the Optimizer swap time zones should be set to complete prior to TimeFinder activity taking place. This should separate the dual-copy sessions, blocking the possibility of the conflicts. However, it is possible that an Optimizer swap will be initiated during a swap time zone, but not complete until some time after the time zone has ended. Therefore, it is important for TimeFinder scripts to gracefully handle TimeFinder BCV establish and incremental reestablish command failures—due to Optimizer still being in the process of swapping volumes (script needs to wait for swap to complete, then attempt the establish). In 5X65, the scripts also need to handle incremental reestablish command failures—due to Optimizer having previously swapped the primary volume (script needs to attempt a full establish).
Appendix B: Using Optimizer from the CLI
To start and stop the Optimizer process on the Symmetrix service processor, use the symoptmz enable and symoptmz disable commands. Once disabled, the Optimizer process on the Symmetrix service processor will still listen for Optimizer clients (SMC, EMC ControlCenter or SYMCLI), but it will not collect statistics or initiate any swaps until it is enabled. To change any Optimizer parameters, Optimizer must be stopped using the symoptmz disable command. The parameters are then set using a command file and the preview, prepare, and commit options. For example, to commit the changes specified in the command file opt_config.txt, issue the command:
symoptmz –file opt_config.txt commit
The preview argument checks that the command file has correct syntax. The prepare argument also checks syntax and, in addition, performs some range checks. The commit argument carries out the same syntax and range checks, and then updates the Optimizer with the modified parameters. It is recommend that a preview be run on your command files, and then any syntax errors corrected. A prepare should then be run and any out-of-range figures should be corrected. Finally, a commit should be done. The commit command will first do a preview and prepare before committing the settings in the command file.
General Optimizer parameters are set using the following commands and syntax in the control file: set control_parms [start_mode=<AUTO | MANUAL>,] [min_perf_period=<min_perf>,] [workload_period=<workload>,] [swap_mode=<AUTO | USER_OK>,] [max_simult_swaps=<max_simult>,] [swap_rate=<max_swaps>]; The following table describes each parameter.
EMC Symmetrix Optimizer A Detailed Review