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SSD Conclusions

Research indicates that SSD can be very valuable to Oracle databases, with the total benefit depending on the type of processing characteristics.

Use SSD for high-impact files – Oracle redo log files, undo segment, and temporary tablespace file will greatly benefit from SSD.

SSD has impressive speed improvements - (Dorsey, 2004) reported a 67% gain (.67x) in data access speed with SSD.  (Morle, 2002) noted a reported a 25% (.25x) increase in system speed with SSD

SSD may shift the Oracle bottleneck to CPU – SSD should only be attempted when CPU consumption (as measured by a STATSPACK top-5 wait event report) is less than 50% of the consumption.  Using SSD will shift the bottleneck from I/O to CPU, and the server may require more CPU’s to improve dispatching, or faster CPU’s (e.g. Itanium2 processors).

Read-intensive system benefit most from SSD – Write-intensive systems, especially those with high buffer invalidations, may only see a marginal speed improvement.

SSD will speed-up access on super-large disks – The 114 gigabyte disk often experiences disk enqueues as competing tasks wait their turn at the read-write heads.  SSD will surely improve throughput for these types of database disks.

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