Database Reference
In-Depth Information
The following are some other software utilities and tools to be aware of:
•
ODAs come with two utilities that allow GUI-based tool sessions to be started. They are VNC
Server and StartX from the ILOM remote console.
•
Server software includes the previously discussed ILOM and ASR facilities. These server
management utilities are an extra Oracle hardware value-added proposition vs. generic
commodity hardware.
•
ODAs pre-deploy a utility called Logwatch, which monitors file system space and
authentication failures and logins through
ssh
. It is automatically scheduled.
ODAs can run other proactive support tools (MOS 1459344.1). A good example is
•
oratop
(1500864.1), which produces a one-panel display of overall database and database server
activity.
ODAs have a unique “worst case” recovery capability. When all is lost, and the server OS disk configurations
are out of action and the databases can't be started, ODAs provide the ability to rebuild the appliance all over again
using a bare metal restore, as long as the source of the problem isn't a major hardware failure. An ODA can be rebuilt
in about two hours using this method. Of course, you will need a backup of your database and any additional objects
that need to be restored to get the ODA in an operational state, such as exports and the OCR for RAC services.
Finally, ODAs come with a license for Oracle's Secure Backup product to use in backing up ODAs.
ODA Performance
The current X3-2 ODA model runs the same compute node model as an Exadata. ODAs do lag the Exadata server
node release cycle. Regardless, they are running the same CPU model most of the time. Exadatas support a memory
expansion from 256G to 512G per server, but ODAs do not. Regardless, logical IO performance on an ODA is excellent.
Another source of ODA performance is that everything is self-contained within the appliance. RAC traffic doesn't
leave the appliance and travel through an external network to communicate between the compute nodes. The two
server nodes and storage units are all next to each other and are connected through high-speed SAS cables. There are
no intervening switches, firewalls, or other external network layers.
ODA physical IO storage performance is good—in fact, better than the typical SAN fiber channel disk. Oracle
has published X3-2 Physical IO benchmarks of 5 milliseconds at 3,500 IOPS on a single storage unit, and 7,000 IOPS
with an additional storage expansion unit. Above those IOPS levels, the service levels decrease. Oracle's ODA X3-2
benchmarks show service levels of 6 to 7 milliseconds at 5,750 IOPS, and 11,500 with a storage expansion rack. These
last numbers are still very good and compare nicely to the levels seen on a well-tuned Fiber Channel disk-based
SAN. However, as the IOPS build above these levels, at some point performance will start to drop noticeably. Since
ODAs come with a lot of memory, caching data in memory is a key scalability factor to avoid reaching the ODA IOPS
limitations.
ODAs do not currently have the supported option to use PCI Flash or SSD. The four SSD drives that come with
ODAs are only supported for use by the online redo logs. ODAs do support expanding storage to NFS, including
Oracle's ZFS storage appliance. The use of DNFS (Direct NFS) to increase performance is supported. However, I'm
not aware of any physical IO performance benchmarks that have been published for ODAs using an NFS storage
extension. While ASM is not supported on the NFS extension, Oracle has announced that ODAs do support Hybrid
Columnar Compression when the NFS mount is an Oracle ZFS storage appliance.
Since Oracle is investing in the ODA platform, the IOPS and disk performance may change with each new
model. You will need to relook at the physical performance and IOPS limits when a new model that replaces the X3-2
is released.
