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The Virtual Tape Paradox
Today, z/OS installations face fundamental
questions regarding the management and future planning of offline
storage resources. While robotic tape systems initially provided solutions
for these problems when they were introduced more than a decade ago,
they have become part of today's problem. Specifically, while the
number of robotic tape subsystems continues to increase in most installations,
the small tape problem (i.e., low cartridge utilization) continues
to compromise the value of offline storage investments.
Virtual tape subsystems have been proposed as yet another solution
to the small tape problem. While most of these subsystems incorporate
service processors, buffer DASD, and tape robotics, other solutions
have been proposed based on host software and large DASD buffers.
These subsystems incorporate technologies ranging from SSA DASD to
log-structured file schemes along with a variety of tape robotic schemes.
The performance claims made for virtual tape subsystems further complicate
the decision process. As a potential buyer, you often find almost
an order of magnitude difference in the performance characteristics
of a prospective virtual tape subsystem when you compare the claims
of the vendor, the critical observations made by competitors, and
the informed opinions of industry pundits, many of whom simply estimate
subsystem performance by talking to the vendors. As a result of these
factors, many installations are making strategic offline storage decisions
without a reliable basis for understanding the true capabilities of
the new technologies.
The PAI/O Driver solution
PAI/O Driver for Tape
from Performance Associates is the solution to this dilemma. Our product
is both technology independent and vendor independent, and it comprises
four distinct parts:
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an acquisition
methodology, |
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a reporting service
based on independent testing of tape and virtual tape subsystems, |
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profiling software
to characterize your virtual tape requirements, and |
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a software program
which allows users to measure and verify virtual tape subsystem
performance. |
Installations can employ PAI/O
Driver for Tape to help in the tape
selection process, to aggressively negotiate acquisition agreements,
or to verify performance clauses in acquisition contracts. It can:
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reduce the cost
of acquiring new tape technology, |
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limit the risks
associated with the acquisition and introduction of new tape
technologies, and |
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support the specification
and enforcement of the vendor's contractual obligations. |
When you have PAI/O Driver for
Tape, you can tell the vendors what you want and verify that you've
gotten it!
The Acquisition methodology
To maximize potential cost benefits and
to minimize your risk during the acquisition process, it is essential
that a request for proposal be technology independent and that effective
performance assurances are included in your acquisition contract.
Our PAI/O Driver
acquisition methodology directs you in meeting these objectives. The
methodology shows you how to acquire a new virtual tape subsystem
which meets all of your specifications at the lowest cost. It shows
you how to specify a technology independent request for proposal.
Moreover, it describes the procedure for including an effective performance
assurance clause in your acquisition contract.
Virtual Tape subsystem profiles
A library of profiles for the most current
virtual tape subsystems is included with our user enterprise-licenses.
An inventory of our profile library is maintained on our home page
at www.perfassoc.com.
The reporting service
In contrast to marketing claims about virtual
tape subsystem performance, the PAI/O
Driver for Tape reporting service
presents and interprets hard repeatable tape subsystem performance
measurements. Rather than being a benchmark of a particular workload,
PAI/O Driver for Tape
employs a specifically designed standard engineering test series to
explore the performance characteristics of any virtual tape subsystem
over a wide variety of configuration alternatives and workload types.
While there is no single test which can provide an absolute evaluation
of the suitability of a virtual tape subsystem for a specific workload
or customer environment, each PAI/O
Driver for Tape subsystem profile
report provides your installation with reliable commentary and analysis.
This is because it is based on hard measurement data, not unsubstantiated
marketing claims or industry hearsay.
We at Performance Associates are committed to the continued measurement
and analysis of new virtual tape subsystem offerings and the publication
of our research reports to licensed user sites. While we will formally
distribute new subsystem profiles to subscribers on a semiannual basis,
we will make informal results available as soon as they are collected.
In the event that you have installed, or have access to, a subsystem
which has not yet been analyzed, we will perform the analysis at our
own expense.
The software
PAI/O Driver for Tape is compatible with
MVS/ESA 5.1 through the most current releases of z/OS and is Year
2000 compliant. It features a standard engineering test series and
includes SAS® workload profiling software for the development
of customer-specific performance verification tests.
Performance Associates services
We can assist you in the measurement, analysis,
and acquisition of new virtual tape subsystems or unique configurations.
Being well versed in the specific requirements presented by state
and federal acquisition regulations, we can help speed the acquisition
process for government agencies and certify the performance of upgrades
over the life of your contract.
Licensing and Additional information
PAI/O Driver for Tape
is an enterprise-licensed product. For additional information and
license terms, please contact Performance Associates at:
Performance Associates, Inc.
P.O. Box 5080
Pagosa Springs, CO 81147-5080
Voice: (970) 731-DASD x104
Fax: (970) 731-1024
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