Expert Oracle Exadata - Parent Directory

CHAPTER 1 WHAT IS EXADATA? Note: Here’s how we cam up with the rough useable space estimates. We took the actual size of the disk andsubtracted 29GB for OS/DBFS space. Assuming the actual disk sizes are 1,861GB and 571GB for high capacity(HC) and high performance (HP) drives, that leaves 1,833GB for HC and 543GB for HP. Multiply that by the numberof disks in the rack (36, 84, or 168). Divide that number by 2 or 3 depending on whether you are using normal orhigh redundancy to get usable space. Keep in mind that the "usable free mb" that asmcmd reports takes intoaccount the space needed for a rebalance if a failgroup was lost (req_mir_free_MB). Usable file space fromasmcmd's lsdg is calculated as follows:Free_MB / redundancy - (req_mir_free_MB / 2)Half and full racks are designed to be connected to additional racks, enabling multiple-rackconfigurations. These configurations have an additional InfiniBand switch called a spine switch. It isintended to be used to connect additional racks. There are enough available connections to connect asmany as eight racks, although additional cabling may be required depending on the number of racks youintend to connect. The database servers of the multiple racks can be combined into a single RACdatabase with database servers that span racks, or they may be used to form several smaller RACclusters. Chapter 15 contains more information about connecting multiple racks.Exadata Database Machine X2-8There is currently only one version of the X2-8. It has two database servers and fourteen storage cells. Itis effectively an X2-2 Full Rack but with two large database servers instead of the eight smaller databaseservers used in the X2-2. As previously mentioned, the storage servers and networking components areidentical to the X2-2 model. There are no upgrades specific to x2-8 available. If you need more capacity,your option is to add another X2-8, although it is possible to add additional storage cells.UpgradesQuarter racks and half racks may be upgraded to add more capacity. The current price list has twooptions for upgrades, the Half Rack To Full Rack Upgrade and the Quarter Rack to Half Rack Upgrade.The options are limited in an effort to maintain the relative balance between database servers andstorage servers. These upgrades are done in the field. If you order an upgrade, the individualcomponents will be shipped to your site on a big pallet and a Sun engineer will be scheduled to installthe components into your rack. All the necessary parts should be there, including rack rails and cables.Unfortunately, the labels for the cables seem to come from some other part of the universe. When we didthe upgrade on our lab system, the lack of labels held us up for a couple of days.The quarter-to-half upgrade includes two database servers and four storage servers along with anadditional InfiniBand switch, which is configured as a spine switch. The half-to-full upgrade includesfour database servers and seven storage servers. There is no additional InfiniBand switch required,because the half rack already includes a spine switch.There is also the possibility of adding standalone storage servers to an existing rack. Although thisgoes against the balanced configuration philosophy, Oracle does allow it. Oddly enough, they do not8