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Oracle Tips by Burleson |
The shift in Oracle bottlenecks
The dramatic decrease in the cost of RAM is radically changing the
Oracle database architecture. In 2005, 100 gigabytes of SSD (i.e.
Texas Memory Systems) can be obtained for about $150,000.
Historically, RAM has been a scarce and expensive resource, and the
DBA was challenged to find the data that was referenced most
frequently to cache on precious RAM media.
This new age of cheap solid state disks has meant a dramatic change
in Oracle database architecture, as the old fashioned model of
disk-based data management is being abandoned in favor of a
cache-based I/O approach.
For years, storage architects have observed the growing divide
between processor performance and storage access times. Remember,
when the CPU waits on storage, the users are waiting on storage.
According to a whitepaper by James Morle, SSD is great for
high-bandwidth I/O components such as Oracle redo logs. The Oracle
redo logs archive the row before images and they are used for data
recovery in the event of a disk crash. Morle notes:
“This is where SSD can help out. By deploying a single
SSD, all redo logs can be located away from the RAID 1+0 array,
whilst providing low latency writes and high bandwidth reads
(for archiving).”
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 |
