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Perhaps the most common questions that our
prospective customers ask us are What is the
PAI/O Driver?, Is it
just a software product?, and How can my shop use PAI/O
Driver in the storage acquisition
process?.
What is the PAI/O Driver?
The PAI/O
Driver is a vendor and technology
independent set of tools and services for evaluating the performance
characteristics of storage subsystems. The host software test component
is employed by licensed enterprise users and site licensed storage
subsystem vendors worldwide, and is used to evaluate storage subsystems.
Our licensed enterprise users receive an extensive set of software
tools, an acquisition methodology, subsystem profiles, profiling software,
and a number of other services. Our vendor site licenses are restricted
to just the host test component of PAI/O
Driver. This restriction helps us
maintain our vendor independence and prevents subsets of the
PAI/O Driver profiles from being
employed for marketing purposes.
The PAI/O Driver
process is detailed in the figure shown above. The small ring towards
the left of the figure depicts the Performance Associates storage
subsystem testing process, the small ring towards the right depicts
the user process, and the larger center ring depicts the delivery
of subsystem profiles to our licensed enterprise users.
Is PAI/O Driver just a software product?
PAI/O Driver
is not just a software product. As part of the user enterprise license
process, Performance Associates has an ongoing commitment to analyze
new and updated vendor storage subsystem offerings. Based on the results
of our standard suite of engineering tests, Performance Associates
prepares and distributes a performance profile of each new and updated
vendor storage subsystem. The results of these tests can then be compared
and contrasted with the results for any other storage subsystem that
was profiled by PAI/O Driver.
Each profile provides an independent and authoritative analysis of
the subsystem architecture, a comprehensive and detailed discussion
of the subsystems performance characteristics, and recommendations
relative to negotiation points that we recommend be employed during
the contracting process.
While there are other organizations that provide information that
may initially sound similar to the PAI/O
Driver storage subsystem profiles,
their observations are based on vendor supplied performance data,
anecdotal observations, or are just reformatted vendor brochures.
Performance Associates is the only source for subsystem profiles that
are based on rigorous independent testing and analysis.
The PAI/O Driver
storage subsystem profiles are distributed to our licensed enterprise
users. These profiles provide our clients an information resource
for their storage acquisition process as is depicted by the large
center ring of the PAI/O Driver
process figure. Quite often, licensed users schedule conference calls
with Performance Associates to discuss the contents of new profiles
that are of particular interest to their enterprise.
How can my shop use PAI/O Driver in
the storage acquisition process?
You can use PAI/O
Driver in the storage acquisition
process. The licensed enterprise user process is shown in the ring
at the right of the figure. The first step in the storage acquisition
process is to characterize storage subsystem requirements. As a licensed
enterprise user, you will receive workload profiling software which
analyzes your SMF data to determine your installations storage
subsystem requirements in terms of access density, data transfer,
access pattern (i.e., random or sequential), blocksize distribution,
and locality of reference. This analysis provides a detailed description
of your installations storage subsystem requirements, which
in turn can be provided to potential vendors during a request for
proposal (RFP) or other bid processes. As a licensed enterprise user
you also receive a recommended acquisition methodology that assists
you in incorporating enforceable performance warranties in acquisition
contracts.
Once provided with your requirements, the storage subsystem vendors
are then free to propose configurations that they warrant will meet
your installations needs. Rather than you being responsible
for specifying key storage subsystem features like cache size, the
burden of configuring a storage subsystem(s) that will meet your installations
needs is placed on the vendor. Each vendor could then provide responses
to the RFP, and you can, in turn, evaluate these responses in terms
of your acquisition criteria.
The PAI/O Driver
storage subsystem performance profiles provide a basis for evaluating
the vendor responses. Specifically, the proposed configurations and
claimed performance for your workload can be compared with the information
contained in the performance profiles. The critical difference of
a storage subsystem acquisition based on the PAI/O
Driver process is that you are provided
with the ability to select the minimum priced storage subsystem which
is guaranteed by the vendor to meet your requirements, not just the
lowest cost per megabyte supported by only the vendors ambiguous
performance claims!
The final step in the acquisition process is performance verification.
Using the workload description that was created during the profiling
process, the PAI/O Driver
can be employed to perform an acceptance test of your new storage
subsystem to verify that the system meets or exceeds the performance
warranty provided by the vendor. If the subsystem passes the test,
it can be introduced into the enterprises storage environment.
Should it fail the verification test, then the enterprise has the
recourse predefined in the acquisition agreement, as well as the ability
to retest the subsystem after the vendor has corrected the performance
deficiency.
Summary
This is the PAI/O
Driver process. The PAI/O
Driver is an independent and respected
storage subsystem performance evaluation tool that is employed by
user enterprises and vendors on a worldwide basis. For licensed enterprise
users, it provides the only source of independent comparative performance
data that is based on actual testing, not just conjecture or anecdotal
observations. Finally, it provides licensed enterprise users a methodology
and a tool set for conducting storage subsystem acquisitions that
incorporate enforceable performance warranties.
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