1. User's Guide
  2. Monitoring Exadata
  3. Monitoring Oracle Exadata System Software Components
  4. Monitoring I/O Resource Management (IORM)
  5. Monitoring I/O Resource Management (IORM) Using Exadata Metrics
  6. Monitoring IORM with Consumer Group Metrics

6.3.8.3.3 Monitoring IORM with Consumer Group Metrics

Consumer group metrics provide information about the I/O load from each consumer group specified in a database resource plan.

Consumer group metrics are identified in the METRICCURRENT, METRICDEFINITION, and METRICHISTORY objects as having objectType=IORM_CONSUMER_GROUP.

Example 6-10 Displaying Consumer Group Metric Definitions

This example shows how to display the consumer group metric definitions that are available in the Oracle Exadata System Software. 

CellCLI> LIST METRICDEFINITION ATTRIBUTES NAME,DESCRIPTION WHERE OBJECTTYPE = IORM_CONSUMER_GROUP
         CG_FC_IO_BY_SEC         "Number of megabytes of I/O per second for this consumer group to flash cache"
         CG_FC_IO_RQ             "Number of IO requests issued by a consumer group to flash cache"
         CG_FC_IO_RQ_LG          "Number of large IO requests issued by a consumer group to flash cache"
         CG_FC_IO_RQ_LG_SEC      "Number of large IO requests issued by a consumer group to flash cache per second"
         CG_FC_IO_RQ_SEC         "Number of IO requests issued by a consumer group to flash cache per second"
         CG_FC_IO_RQ_SM          "Number of small IO requests issued by a consumer group to flash cache"
         CG_FC_IO_RQ_SM_SEC      "Number of small IO requests issued by a consumer group to flash cache per second"
         CG_FD_IO_BY_SEC         "Number of megabytes of I/O per second for this consumer group to flash disks"
         CG_FD_IO_LOAD           "Average I/O load from this consumer group for flash disks"
         CG_FD_IO_RQ_LG          "Number of large IO requests issued by a consumer group to flash disks"
         CG_FD_IO_RQ_LG_SEC      "Number of large IO requests issued by a consumer group to flash disks per second"
         CG_FD_IO_RQ_SM          "Number of small IO requests issued by a consumer group to flash disks"
         CG_FD_IO_RQ_SM_SEC      "Number of small IO requests issued by a consumer group to flash disks per second"
         CG_FD_IO_TM             "The cumulative latency of reading or writing blocks by a consumer group from flash disks"
         CG_FD_IO_TM_LG          "The cumulative latency of reading or writing large blocks by a consumer group from flash disks"
         CG_FD_IO_TM_LG_RQ       "The rate which is the average latency of reading or writing large blocks per request by a consumer group from flash disks"
         CG_FD_IO_TM_RQ          "The rate which is the average latency of reading or writing blocks per request by a consumer group from flash disks"
         CG_FD_IO_TM_SM          "The cumulative latency of reading or writing small blocks by a consumer group from flash disks"
         CG_FD_IO_TM_SM_RQ       "The rate which is the average latency of reading or writing small blocks per request by a consumer group from flash disks"
         CG_FD_IO_UTIL           "Percentage of flash resources utilized by this consumer group"
         CG_FD_IO_UTIL_LG        "Percentage of flash resources utilized by large requests from this consumer group"
         CG_FD_IO_UTIL_SM        "Percentage of flash resources utilized by small requests from this consumer group"
         CG_FD_IO_WT_LG          "IORM wait time for large IO requests issued to flashdisks by a consumer group"
         CG_FD_IO_WT_LG_RQ       "Average IORM wait time per request for large IO requests issued to flash disks by a consumer group"
         CG_FD_IO_WT_SM          "IORM wait time for small IO requests issued to flashdisks by a consumer group"
         CG_FD_IO_WT_SM_RQ       "Average IORM wait time per request for small IO requests issued to flash disks by a consumer group"
         CG_IO_BY_SEC            "Number of megabytes of I/O per second for this consumer group to hard disks"
         CG_IO_LOAD              "Average I/O load from this consumer group for hard disks"
         CG_IO_RQ_LG             "Number of large IO requests issued by a consumer group to hard disks"
         CG_IO_RQ_LG_SEC         "Number of large IO requests issued by a consumer group to hard disks per second"
         CG_IO_RQ_SM             "Number of small IO requests issued by a consumer group to hard disks"
         CG_IO_RQ_SM_SEC         "Number of small IO requests issued by a consumer group to hard disks per second"
         CG_IO_TM_LG             "The cumulative latency of reading or writing large blocks by a consumer group from hard disks"
         CG_IO_TM_LG_RQ          "The rate which is the average latency of reading or writing large blocks per request by a consumer group from hard disks"
         CG_IO_TM_SM             "The cumulative latency of reading or writing small blocks by a consumer group from hard disks"
         CG_IO_TM_SM_RQ          "The rate which is the average latency of reading or writing small blocks per request by a consumer group from hard disks"
         CG_IO_UTIL_LG           "Percentage of disk resources utilized by large requests from this consumer group"
         CG_IO_UTIL_SM           "Percentage of disk resources utilized by small requests from this consumer group"
         CG_IO_WT_LG             "IORM wait time for large IO requests issued to hard disks by a consumer group"
         CG_IO_WT_LG_RQ          "Average IORM wait time per request for large IO requests issued to hard disks by a consumer group"
         CG_IO_WT_SM             "IORM wait time for small IO requests issued to hard disks by a consumer group"
         CG_IO_WT_SM_RQ          "Average IORM wait time per request for small IO requests issued to hard disks by a consumer group"

Note the following additional details:

  • The consumer group and database for the metric are specified by the metricObjectName attribute of the METRICCURRENT and METRICHISTORY objects. The name is formed by the database name followed by a period (.) and the consumer group name. For example, for a database named PRODUCTIONDB and a consumer group named OLTP, the metricObjectName would be PRODUCTIONDB.OLTP.

  • For metrics that relate to I/O load (for example, CG_FD_IO_LOAD and CG_IO_LOAD), see the additional information relating to CD_IO_LOAD.

  • Starting with Oracle Exadata System Software release 19.1.0, if you configured ASM-scoped security for the Oracle Automatic Storage Management (Oracle ASM) cluster used by the database, then the database name is prefixed with the Oracle ASM cluster name.

  • For cumulative metrics, the metric value for a specific time period can be determined by subtracting values from different collectionTime periods.

  • For rate metrics, the time period for the metric value is over the previous minute.

  • In the metric descriptions, small I/O requests are less than or equal to 128 KB, and large I/O requests are larger than 128 KB.

  • All consumer group cumulative metrics are reset to zero whenever a category, IORM, or any database resource plan is modified.

  • To list the current metrics for consumer groups, use the following CellCLI command: 

    CellCLI> LIST METRICCURRENT WHERE objectType = 'IORM_CONSUMER_GROUP' AND metricValue != 0 ATTRIBUTES name, metricObjectName, metricValue, collectionTime

  • For Oracle ASM and all other databases, metrics are only provided for the BACKGROUND and OTHER consumer groups. The BACKGROUND consumer groups are:

    • _ORACLE_BACKGROUND_GROUP_: High-priority I/O requests from Oracle Database background processes

    • _ORACLE_MEDPRIBG_GROUP_: Medium-priority I/O requests from Oracle Database background processes

    • _ORACLE_LOWPRIBG_GROUP_: Low-priority I/O requests from Oracle Database background processes

Parent topic: Monitoring I/O Resource Management (IORM) Using Exadata Metrics