Expert Oracle Exadata - Parent Directory

CHAPTER 7 RESOURCE MANAGEMENTAn IORM_MODE ranging between 1 and 2, or between 2 and 3, indicates the mode was changed duringthe polling period. It also indicates the proximity to the IORM objective. This might occur, for example, ifthe objective was set to auto and during the polling period the workload shifted significantly from smallI/O requests to large I/O requests. By comparing the IORM_MODE metric over time, you can determine howvolatile your workload is. A constantly changing workload may give insight into where I/O ResourceManagement is needed the most.The metrics we’re interested in for IORM monitoring have an objectType of IORM_DATABASE ,IORM_CATEGORY, and IORM_CONSUMER_GROUP. These metrics are further organized by the name attribute inthe METRICCURRENT object. The name of the metric is a concatenation of abbreviations that indicate thetype of I/O consumer group, the type of storage device, and a descriptive name. The elements of the nameattribute appear as follows:{consumer_type}_{device type}_{metric}Where consumer_type represents the IORM resource group and is one of these:DB = Interdatabase IORM PlanCT = Category IORM PlanCG = Intradatabase IORM PlanAnd device_type is the type of storage that serviced the I/O request and is one of the following:FC = flash cacheFD = Flash-based grid disk‘’ = If neither of the above, then the metric represents I/O to physical disksThe last part of the attribute, {metric}, is the descriptive name of the metric. The metric name may befurther qualified by SM’or LG, indicating that it represents small I/O requests or large I/O requests. Forexample:CG_FC_IO_RQ_LG: The total number of large I/O requests serviced from flashcache (FC), for DBRM consumer groups.CG_FD_IO_RQ_LG: The total number of large I/O requests serviced from flashbasedgrid disks (FD), for DBRM consumer groups.CG_IO_RQ_LG: The total number of large I/O requests serviced from physical disks(grid disks), for DBRM consumer groups.Table 7-5 describes each of the IORM consumer group performance metrics captured by cellsrv usingthese abbreviations.222