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Oracle Tips by Burleson |
Removing Bandwidth Saturation with SSD
DBA’s who are experiencing Oracle RAC databases that are being hit
by a large number of concurrent users should consider storing all
concurrent access data files on SSD. This will make sure that
storage is not a bottleneck for the application and maximize the
utilization of servers and networks. I/O wait time will be minimized
and servers and bandwidth will be fully utilized.
For example, the Texas Memory Systems RamSan has 3,000 MB per second
bandwidth and 250,000 I/Os per second sustained which means that it
can simultaneously boost performance for multiple servers. The
RamSan-320 uses a three-disk RAID back-up system, in addition to
internal batteries, component redundancy, and hot-swap capabilities,
for added data protection. This is a significant advance in
reliability for 24 X 7 data center operations with critical
applications.
There are two main benefits to having high bandwidth:
- Some RAC applications require high bandwidth. Good examples
include Oracle RAC video-on-demand databases where thousands of
users must access the video files in different spots.
- High bandwidth enables the SSD to be shared across multiple
hosts without impacting performance. This feature is critical
for Oracle RAC systems.
It is important to remember that there is one huge difference
between disk and SSD. Solid state disks have the high bandwidth
to sustain random data streams while traditional platter disks
can only sustain high bandwidth numbers with sequential data
streams.
I/O bandwidth can be conceptualized as the width of the highway
between the device and the Oracle SGA. Traditional disk is a one
lane dirt road while SSD is an eight lane superhighway.
The RAM-to-RAM transfer of SSD to the Oracle RAC data buffer cache
can have hundreds of times of the throughput of platter disks and
can help ensure that the CPU’s are fully utilized.
The above book excerpt is from:
Oracle RAC
& Grid Tuning with Solid State Disk
Expert Secrets for High Performance Clustered Grid Computing
ISBN:
0-9761573-5-7
Mike Ault, Donald K. Burleson
http://www.rampant-books.com/book_2005_2_rac_ssd_tuning.htm |
