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Oracle Database Tips by Donald Burleson
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A Look
Into the Future
Anyone paying attention while reading this book
should be coming to a conclusion that disks will soon be relegated to
the job of acting as backing store to massive arrays of solid state
drives. It is an inescapable result of the massive improvements in
memory sizes and huge reductions in memory cost.
Even Oracle, with their moves towards CPU-based
costing and away from I/O based costing models in the cost based
optimizer, can see the writing on the wall: disks will soon be for
backup only with the real power resting in solid state memory based
data storage.
For years, Oracle and other database providers
focused considerable time and money on squeezing the last drop of
performance out of disk arrays. This consisted of tortuously
minimizing I/O path length, reducing code branches, improving the bus
architectures simply because the disks at the end of the chain just
could not get much faster. Now, other users can reap the benefits of
all that work by replacing the spinning rust with SSD.
What will this mean in the future? First, Oracle
and other manufacturers will need to concentrate on the database
internals to fully utilize the power and speed provided by SSD.
Eventually, the entire I/O subsystem will be replaced by the memory
subsystem. Gone will be the host bus adapters, fibre connects, and
other disk related architectures as more efficient methods are
developed for accessing this high speed, high capacity SSD resource.
Future generations of users will ask if mechanical devices were ever
really used to store data.
This is an excerpt from the book
Oracle RAC & Tuning with Solid State Disk.
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 |
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IBM |
RamSan-400 |
RAM SSD |
Fibre
Channel
InfiniBand
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3,000MB/s random
sustained external throughput, 400,000 random IOPS |
|
Violin Memory |
Violin 1010 |
RAM SSD
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PCIe
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1,400MB/s read,
1,00MB/s write with ×4 PCIe, 3 microseconds latency |
|
Solid Access Technologies |
USSD 200FC |
RAM SSD |
Fibre Channel
SAS
SCSI
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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:
|
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Avg. Read speed
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Avg. write speed
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Platter disk
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10.0 ms.
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7.0 ms.
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DRAM SSD
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0.4 ms.
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0.4 ms.
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Flash SSD
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1.7 ms.
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94.5 ms.
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