 |
|
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 RamSanhas 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 (Figure 2.5).
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 cachecan 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 & Tuning with
Solid State Disk
Expert Secrets for High
Performance Clustered Grid Computing
ISBN
0-9761573-5-7
Donald K. Burleson & Mike Ault
http://www.rampant-books.com/book_2005_2_rac_ssd_tuning.htm
|
