Expert Oracle Exadata - Parent Directory

CHAPTER 7 RESOURCE MANAGEMENTCategory MetricsIORM prioritizes I/O in a hierarchical manner (illustrated in Figure 7-12). Our Category Plan is at the topof the hierarchy, so that’s where we’ll start. Recall that our plan allocates I/O for the APPS and BATCHcategories at a 70% / 30% ratio on level 1. At level 2, the OTHER category is allocated 100% of the unusedI/O from the APPS and BATCH categories. Figure 7-16 shows the ratio of I/O requests serviced per second(in megabytes), on behalf of each category. Remember that the load from each category was the same.Notice that APPS_CATEGORY received approximately 63% of the I/O, while BATCH_CATEGORY received about30%. The OTHER category received the remaining 8.3% of I/O. You may be surprised at the amount of I/Othat OTHER received. This was because of the allocated but unused I/O resources it inherited from theAPPS and/or BATCH categories at level 1.Figure 7-16. I/O operations scheduled per second, by categoryDatabase MetricsNext in the IORM hierarchy is our Interdatabase IORM Plan. This plan calls for the SCRATCH database tobe allocated 60% of the I/O at level 1, and the SNIFF database to receive 80% at level 2. Figure 7-17 showsthe ratio of I/O requests scheduled on behalf of the SCRATCH and SNIFF databases. Again, the number ofrequests coming from these databases was the same. According to the metrics collected during ourstress test, I/O was allocated to the SCRATCH and SNIFF databases at a ratio of 64% / 36% respectively.230