Expert Oracle Exadata - Parent Directory

CHAPTER 7 RESOURCE MANAGEMENTdbPlan:status:inactiveBecause we dropped the Interdatabase plan from the previous exercise, the dbPlan field is empty.We’ll reinstall that plan again when we are ready to test our resource plans. Note that the IORM Plan isinactive. We’ll leave our Category Plan inactive for now. Later, in the IORM metrics section of thechapter, we’ll test our Category IORM Plan and discuss how the effects of IORM can be monitored at thestorage cells.Intradatabase IORMIn the case of Interdatabase I/O resource management, cellsrv identifies I/O requests by a tagcontaining the database name issuing the request. Category I/O resource management works in asimilar way, using a tag in the I/O request to identify the category issuing the request. The third, andfinal, type of I/O resource management available on the Exadata platform is Intradatabase IORM.Intradatabase I/O resource management is configured in each database using DBRM’s managementattributes, MGMT_P1..8. You may recall from earlier in the chapter that the MGMT_Pn attributes are whatDBRM uses to manage CPU resources. DBRM uses CPU allocation directives to define priorities amongconsumer groups within the database. By tying I/O allocations to CPU allocations, IORM carries forwardthese priorities to the storage layer, thus maintaining a consistent provisioning scheme for both.Configuring Intradatabase IORMIntradatabase IORM is not terribly difficult to implement. In fact, in a manner of speaking, we havealready done so. In the DBRM section of this chapter, we created consumer groups, resource plans, andplan directives that managed CPU resources within the SCRATCH database. On the Exadata platform,when a DBRM resource plan is activated, the database transmits a description of the plan, includingMGMT_Pn directives, to all cells in the storage grid. This also happens any time cellsrv is started on thestorage cells. So whether you’re installing a new cell into the storage grid, rebooting a cell, or bouncingcellsrv services, your Intradatabase resource plan will be pushed to the cell automatically. If IORM isactive on the cell, it will generate an Intradatabase Plan and begin managing I/O priorities according toyour resource directives. Figure 7-11 illustrates the process of configuring and activating IntradatabaseIORM.214