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http://searchoracle.techtarget.com/originalContent/0,289142,sid41_gci1264601,00.html
Grid computing adoption slow amid fears of complexity
By Elisa Gabbert, Associate Editor
18 Jul 2007 | SearchOracle.com
While many Oracle shops already enjoy the high-availability benefits of
clustering, the perceived complexity of grid computing still scares some users
off, a new survey has found.
A recent survey of Independent Oracle Users
Group (IOUG) members reveals that adoption of Oracle
Real Application Clusters (RAC) and other clustering products is now
widespread, but grid
computing is still a fledgling technology. The results also suggest that
some Oracle users aren't quite sure of the differences between RAC and grid.
The survey pooled 220 responses from IOUG members representing a wide range
of industries. Half of those surveyed were database administrators (DBAs), with other respondents including IT managers,
directors, CIOs and consultants. Most organizations
represented in the survey have both Oracle 9i and Oracle 10g databases in
production.
More than a third of those surveyed have already implemented RAC, and an
equal number (35%) have a third-party clustering product in place. In contrast,
only about one in four respondents currently have Oracle Grid in production or
are planning a grid implementation. Among the remaining 75% of respondents,
just over half reported no plans for grid at all, with another 12% unsure about
grid plans and 11% unclear on the difference between RAC and grid. The survey
revealed that complexity is the main reason for resistance to grid computing.
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Are fears about grid deployment founded?
Concerns about the considerable amount of time and energy it takes to
implement grid computing are valid, said Ari Kaplan, president of the IOUG, but
as with any new technology, organizations need to expend resources to realize a
return on investment.
"There are clear business benefits [with grid] -- availability and
performance -- but there are also challenges. It requires additional training
and additional hardware," he said.
According to Bill
Cullen, an Oracle DBA and independent consultant who specializes in
high-availability technologies, grid fears are not surprising.
"Tech managers are always leery of wasting money on the five-dollar
solution for the five-cent problem," Cullen said. "I'm not saying
that's what grid is, but that's what decision-makers are fearful of."
Cullen said that there is currently a shortage of grid database expertise,
and as a result, "managers are scared of the complexity, training costs
and [the potential for] mucking up existing production applications that are
working well."
Much of the concern about grid's complexity may be a holdover from earlier
versions of the technology, added Kaplan.
"[Oracle] Parallel Server and early versions of grid were very complex
and challenging to implement, but with 10g [Grid], Oracle has truly made leaps
and bounds in ease of installation," Kaplan said. "People may have
tried it and not had success and haven't taken a look at it again."
Cullen added that reluctance to deploy new technologies is simply the norm
in IT.
"I remember when managers were worried about the complexity of the 7.3 database,"
he said. "I may not go as far as to say [that concerns about complexity
are] unfounded, but it is certainly missing the forest for the trees, because
the reality is that grid reduces complexity, makes larger environments more
manageable and lowers costs in the long run."
According to the survey, among sites that do have grid in place, data
warehousing and business intelligence are the most prevalent application areas.
Almost three out of four of these sites report direct benefits from grid, with
45% citing increased availability of applications and services. Other reported
benefits include enhanced failover, backup and recovery and increased
scalability.
While most grid sites currently only have two to four nodes in production,
almost one in four respondents said they plan to deploy 12 or more nodes within
a year. This high number surprised Kaplan, but he was glad to see people taking
more advantage of the potential benefits of having more nodes.
"You get the high availability with two nodes," he said, "but
beyond two nodes you start to see more performance improvements."
The survey also revealed that many companies are moving from clustering to
grid. Half of RAC users are already moving to grid or are planning to make the
switch, citing greater flexibility as the main reason. According to Kaplan,
grid is more powerful because it offers more redundancy, not just in the
database but in the application servers and elsewhere.
"The more redundancy you build in, the higher the availability and the
lower the risk," Kaplan said.
How is Oracle Grid different from RAC?
Oracle RAC is an instance of a single database and application running
across multiple clustered processors. A group of computers in a cluster are
organized to perform the same function. According to the executive summary of
the IOUG survey, clusters are generally perceived as a strategy for failover --
if one of the nodes goes down, the application can keep running on another
processor.
For RAC, clustered processors must be identical. Grid architecture, in
contrast, does not have this requirement. A grid is a collection of resources
and may consist of multiple clusters. Grid systems are mainly perceived as a
strategy for workload balancing, enabling the activation of new nodes as demand
for computing power increases, according to the summary report.
Some survey respondents indicated confusion about the difference between RAC
and grid. "Some people use [the terms] synonymously," Kaplan said.
"People are very familiar with Oracle RAC because it's been out so long --
it's an actual product. 'Grid' really refers to a
larger thing. Oracle RAC is just one piece of the grid."
According to Cullen, there's conflicting information and confusion even
among the pros about the potential benefits of RAC versus grid.
"I don't think even the experts agree on the differences between
clustering and grid, at least as far as the benefits between the two," he
said. "In essence, grid allows you to borrow, distribute and reallocate
your resources to where you need it, when you need it. It eases management and
lowers costs by utilizing less expensive hardware and diminishing unused or
underutilized resources. Many sites miss this concept and view Grid as
RAC-Plus."
Cullen also found the concept of moving from RAC to grid
problematic.
"While I know of many RAC installations without [Oracle] Grid and
understand you can have grid without RAC, I am not sure I get the scenarios
where the business requirements would dictate abandoning RAC for a solely grid
architecture," he said.
What does a typical RAC or grid implementation look like?
Both Kaplan and Cullen report that Linux is the operating system of choice
for RAC and grid deployments.
"People seem to like to use Oracle's Grid Control over at least eight
version 10gR2 blade nodes using ASM [Automatic Storage Management], with Linux
being the preferred OS," Cullen said. "Linux is popular because it
runs very nicely on smaller machines with one to four CPUs, and it is much more
cost-friendly when you start scaling out multiple nodes."
Kaplan agreed.
"Red Hat Linux is extremely popular -- in my experience, the most popular -- followed by Solaris and HP-UX and then AIX," he said.
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