Databases Reference
In-Depth Information
database releases available when specific models were introduced. Upgrades to newer
Oracle database releases are supported on older platforms.) The Linux operating system
has proven to be the most popular choice on these platforms, though some models also
support Solaris.
Details of the server and storage configurations change as Oracle releases new versions
of Exadata. All Oracle Exadata Database Machine versions consist of Database Server
nodes and Exadata Storage Server cells and house at least two InfiniBand switches. A
third switch, called a spine switch, is provided on configurations designed to scale be‐
yond a single Rack. The Database Server nodes are configured with two CPUs (especially
appropriate for Oracle database applications that scale best with RAC) or eight CPUs
(especially appropriate for database applications that scale best on SMP systems). Each
node contains memory, local storage for the Oracle Database Server node software,
InfiniBand, and Ethernet connections. Ethernet connections are used for administra‐
tion (Exadata contains its own Ethernet switch for the administration network) and for
user access to the databases. Eight dual-processor nodes or two 8-processor nodes make
up a Full Rack configuration.
Exadata Storage Server cells each contain 12-high performance or high-capacity disk
drives, Flash storage in the form of PCI cards, and InfiniBand connections. A Full Rack
contains 14 Storage Server cells. With today's disk capacities, a Full Rack can contain in
excess of 500 TB of disk. The Smart Flash Cache storage provides an intermediate area
(measuring into the TBs) that is used by the database for a cache between memory and
storage. Objects can be pinned into the Flash Cache using the ALTER TABLE statement.
You can also create Flash Disks using this Flash Cache, keeping in mind that this is a
volatile area (so a backup strategy should also be put in place).
Figure 12-3
illustrates
an Oracle Database Machine Full Rack configuration.
Where nodes containing two CPUs are deployed, partial Rack configurations are avail‐
able in similar ratios of Database Server nodes to Exadata Storage Server cells as present
in the Full Rack. For example, a Half Rack contains four Database Server nodes and
seven Exadata Storage Server cells. For scaling beyond a single Full Rack, the InfiniBand
spine switch in the Rack provides enough free ports for connecting up to eight Full
Racks together without the need for another external switch.
The Exadata Storage Server software provides Oracle database optimization not avail‐
able for non-Exadata storage devices. This software can implement smart scans, which
occur in storage and utilize the CPUs and memory in the Exadata Storage Server cells
for selection and other operations. Other Oracle database functionality is also pushed
to the Exadata Storage cells and performed in parallel. Hybrid Columnar Compression
(HCC) transparently organizes and stores data by table column increasing compression
ratios, typically by 10 times for data warehouses, thus improving scans. Individual row
organization is self-contained in compression units so minimal I/O is required to re‐
