Call (800) 766-1884 for Oracle support & training
Free Oracle Tips


Oracle Consulting Support
Oracle Upgrades
Use New Oracle Features
Oracle Replication Support
Oracle Training
Remote Oracle DBA
System Documentation
Oracle Tips
Oracle Performance
 

Free Oracle Tips


 

HTML Text

BC Oracle tuning

Oracle training

Oracle support

Remote Oracle

 

 

   
  Oracle Tips by Burleson

SSD Benchmark Hypothesis

Now that the issues surrounding SSD in an Oracle environment have been covered, it is time to hypothesize about the results of the benchmark tests. 

In reviewing the existing research and applying logic to the results, large performance gains can be realized by placing specific types of databases on SSD. Specifically databases that are predominantly read based, such as decision support (DSS) or data warehouse, should benefit the most. In order to determine if this is indeed the case, use the TPCH benchmark, which is designed for DSS testing.

The central issue of this study is to determine the benefit of SSD for Oracle under these conditions:

No SSD with a super-large Oracle data buffer – This can minimize PIO with only one physical read into the data buffer, but cause LIO overhead.

SSD with a tiny Oracle data buffer – This makes PIO faster, but will cause repeated LIO overhead as data blocks are aged-out of the Oracle data buffer.  It is expected that LIO overhead would be huge with high latch contention, buffer busy waits, and free buffer waits.

SSD for files with large Oracle Data buffer cache – This is duplicating RAM but it would relieve the LIO issue.

Assuming that SSD is far faster for PIO, the issue of duplicitous Oracle activity still remains.  At PIO time, the data block must still be read into db_cache_size and then a consistent get is required to deliver the data block to the requesting program. Hence, RAM resources appear to be better allocated directly to db_cache_size instead of using the RAM with SSD.

Specific architectures

Large data buffers with SSD for:

  • Redo log files

  • Undo segments

  • Temporary tablespace blocks

Predictions

If it is assumed that SSD is far faster for PIO, the issue of duplicitous Oracle activity still remains.  At PIO time, the data block must still be read into db_cache_sizeand then a consistent get is required to deliver the data block to the requesting program. Hence, RAM resources appear to be better allocated directly to db_cache_size instead of using RAM with SSD.

The benchmark study that was created specifically to test these hypotheses and show conclusively how Oracle functions with solid-state disk will follow in the next Chapter.


The above book excerpt is from:

Oracle Solid State Disk Tuning

High Performance Oracle tuning with RAM disk

ISBN 0-9744486-5-6  

Donald K. Burleson & Mike Ault

http://www.rampant-books.com/book_2005_1_ssd.htm

  
 

Oracle performance tuning software 
 
 
 
 

Oracle performance tuning book

 

 
 
 
Oracle performance Tuning 10g reference poster
 
 
 
Oracle training in Linux commands
 
Oracle training Excel
 
Oracle training & performance tuning books
 

 

   

Copyright © 1996 -  2014 by Burleson. All rights reserved.

Oracle® is the registered trademark of Oracle Corporation. 

Hit Counter