Expert Oracle Exadata - Parent Directory

CHAPTER 14 STORAGE LAYOUTConfiguration OptionsExadata represents a substantial investment for most companies. For one reason or another, we findthat many companies want to buy a full or half rack for consolidating several database environments.Exadata’s architecture makes it a very good consolidation platform. These are some of the mostcommon configurations we’ve seen:• A full rack servicing development, test, and production• A full rack servicing several, independent production environments• A half rack servicing development and test• Isolating a scratch environment for DBA testing and deploying software patchesFor each of these configurations, isolating I/O to specific database servers may be a keyconsideration. For example, your company may be hosting database environments for external clientsthat require separation from other database systems. Or your company may have legal requirements toseparate server access to data. Another reason for segmenting storage at the cell level may be to providean environment for DBA training, or testing software patches. There are two ways to isolate Exadatastorage cells, by network access and by storage realm.Isolating Storage Cell AccessRecall that ASM gains access to grid disks through the Infiniband network. This is configured by addingthe IP address of storage cells in the cellip.ora file. For example, in a full rack configuration, all 14storage cells are listed as follows:[enkdb02:oracle:EXDB2] /home/oracle> cat /etc/oracle/cell/network-config/cellip.oracell="192.168.12.9"cell="192.168.12.10"cell="192.168.12.11"cell="192.168.12.12"cell="192.168.12.13"cell="192.168.12.14"cell="192.168.12.15"cell="192.168.12.16"cell="192.168.12.17"cell="192.168.12.18"cell="192.168.12.19"cell="192.168.12.20"cell="192.168.12.21"cell="192.168.12.22"When ASM starts up it interrogates the storage cells on each of these IP addresses for grid disks itcan use for configuring ASM disk groups. We can easily segregate storage cells to service specificdatabase servers by removing the IP address of cells that should not be used. Obviously this is notenforced by any kind of security but it is an effective, simple way of pairing up database servers with thestorage cells they should use for storage. Table 14-5 illustrates a configuration that splits a full rack intotwo database, and storage grids. Production is configured with six database servers and 11 storage cells,while Test is configured for two database servers and three storage cells.485