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Comparing the Different Scenarios

The main focus for testing was determining the raw performance of SSD verses disk technology. The following is a list of the scenarios tested:


  • SSD performance with the DSS type queries with no logging and no archive logging

  • SSD Performance with the DSS type queries with logging and archive logging

  • Regular Disk Performance for DSS type queries with no logging and no archive logging

  • Regular Disk performance for DSS type queries with NL and NAL and temporary and undo segments on SSD

  • Regular disk performance for DSS type queries with NL and NAL and data on the SSD

  • Regular disk performance for DSS type queries with NL and NAL and memory reduced.


The SSD scenarios will be examined first to determine what conclusions can be reached.

SSD Scenario Comparisons

Overall SSD performance was uniform with the exception of the initial run when memory areas used in later queries where being loaded. Assuming that the data loaded and then read from Oracle memory structures was nearly identical for each set of identical queries with identical initialization parameters, the SSD outperformed the regular disks for DSS queries by at least two orders of magnitude.

In comparing the total time for all queries to complete, the SSD database out performed the normal disk databases by a minimum factor of 179. Recall that several of the normal disk queries had to be halted at the 24 hour point in order to be able to complete the query runs in a reasonable amount of time. Therefore the true magnitude of the difference in times between the SSD and normal disk runs is technically much higher. Table 4.1 (above) lists the results form the 7 SSD runs.

Disregarding runs that followed a database restart, the performances across the various scenarios were within a couple of percent of each other. Runs 1 and 7 both followed restarts and also showed comparable results. Documented research exists that indicates that these results will hold even with multi-user access. The reason being that no disk latency, read blocking, or other disk access issues are encountered with SSD technology. In fact, until the I/O channels get flooded, all users should experience similar performance. With proper configuration, transfer rates of up to 2 gigabytes per second are possible using SSD technology.

While some queries required up to 10 minutes to achieve results on the SSD array, this was still substantially less time than the same queries required on either the SCSI or ATA arrays. Since some of the SCSI and ATA queries never finished within the boundaries of our test configurations, it is not possible to know how long they would have taken. Now the SCSI and ATA scenarios will be examined.


See code depot for complete scripts

This is an excerpt from the book Oracle Solid State Disk Tuning.  You can get it for more than 30% by buying it directly from the publisher and get immediate access to working code examples.

Market Survey of SSD vendors for Oracle:

There are many vendors who offer rack-mount solid-state disk that work with Oracle databases, and the competitive market ensures that product offerings will continuously improve while prices fall.  SearchStorage notes that SSD is will soon replace platter disks and that hundreds of SSD vendors may enter the market:

"The number of vendors in this category could rise to several hundred in the next 3 years as enterprise users become more familiar with the benefits of this type of storage."

As of January 2015, many of the major hardware vendors (including Sun and EMC) are replacing slow disks with RAM-based disks, and Sun announced that all of their large servers will offer SSD.

Here are the major SSD vendors for Oracle databases (vendors are listed alphabetically):

2008 rack mount SSD Performance Statistics

SearchStorage has done a comprehensive survey of rack mount SSD vendors, and lists these SSD rack mount vendors, with this showing the fastest rack-mount SSD devices:

manufacturer model technology interface performance metrics and notes
IBM RamSan-400 RAM SSD

Fibre Channel

3,000MB/s random sustained external throughput, 400,000 random IOPS
Violin Memory Violin 1010 RAM SSD


1,400MB/s read, 1,00MB/s write with ×4 PCIe, 3 microseconds latency
Solid Access Technologies USSD 200FC RAM SSD

Fibre Channel

391MB/s random sustained read or write per port (full duplex is 719MB/s), with 8 x 4Gbps FC ports aggregated throughput is approx 2,000MB/s, 320,000 IOPS
Curtis HyperXCLR R1000 RAM SSD

Fibre Channel

197MB/s sustained R/W transfer rate, 35,000 IOPS

Choosing the right SSD for Oracle

When evaluating SSD for Oracle databases you need to consider performance (throughput and response time), reliability (Mean Time Between failures) and TCO (total cost of ownership).  Most SSD vendors will provide a test RAM disk array for benchmark testing so that you can choose the vendor who offers the best price/performance ratio.

Burleson Consulting does not partner with any SSD vendors and we provide independent advice in this constantly-changing market.  BC was one of the earliest adopters of SSD for Oracle and we have been deploying SSD on Oracle database since 2005 and we have experienced SSD experts to help any Oracle shop evaluate whether SSD is right for your application.  BC experts can also help you choose the SSD that is best for your database.  Just  call 800-766-1884 or e-mail.:  for SSD support details.

DRAM SSD vs. Flash SSD

With all the talk about the Oracle “flash cache”, it is important to note that there are two types of SSD, and only DRAM SSD is suitable for Oracle database storage.  The flash type SSD suffers from serious shortcomings, namely a degradation of access speed over time.  At first, Flash SSD is 5 times faster than a platter disk, but after some usage the average read time becomes far slower than a hard drive.  For Oracle, only rack-mounted DRAM SSD is acceptable for good performance:

Avg. Read speed

Avg. write speed

Platter disk

10.0 ms.

  7.0 ms.


 0.4 ms.

  0.4 ms.

Flash SSD    

 1.7 ms.

 94.5 ms.



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