Managing storage as it proliferates in an enterprise is a big
challenge. The key to storage management is
capacity planning -- understanding how much storage is
available, knowing where the storage is located and allocating
storage resources to users and applications.
Today's storage managers must see beyond the bytes to understand
the nature, attributes and value of the data itself. Once
administrators understand the data, know who owns it and see how
the data is being used, they can make smart capacity planning
decisions about enterprise storage and data protection.
All the hype surrounding storage management products can
complicate the process of choosing a storage management product.
Having the ability to manage multiple storage systems through a
single product is a key criteria. But after that, you'll need to
plod through an overwhelming array of features and capabilities to
identify the best tools for your situation. This section of our
guide to SAN expansion explains how to identify the best storage
management and capacity planning tools.
Best Practice No. 1: Understand storage utilization and other
key attributes
The first benchmark for a storage management and capacity
planning tool is to identify the available storage and report how
much of your total storage capacity is actually being used. Any
storage management tool should be able to provide this type of
information, but it must interoperate with your storage platforms.
Storage area network (SAN) storage typically runs at 60% to 85%
utilization. If your SAN consistently runs at less then 60%
utilization, you have
excess storage capacity that you could have
purchased later, in all probability at a lower cost . If storage
utilization is more than 85%, you should probably add more
storage soon to avoid application performance problems.
A good capacity planning tool will monitor storage utilization
over time and offer users storage purchase recommendations.
Ideally, the amount and timing of any storage upgrade
recommendations will prevent any application performance problems,
while avoiding wasteful overbuying. Capacity planning tools
typically get more accurate over time as near-term and long-term
trends can be tracked.
Once you have a handle on storage utilization, examine all the
available storage characteristics, such as response time, latency,
IOPS, throughput, bandwidth and power demands. "A balanced plan
should address performance, availability, capacity and energy
consumption (PACE)," says Greg Schulz, founder and senior analyst
at the Storage IO Group.
Best Practice No. 2: Translate growth rates into
costs
Managing storage growth is the best way to manage storage costs,
so it's important to understand how your compound annual storage
growth rate relates to your storage budget. "The magic number is
55%," says Phil Goodwin, president of Diogenes Analytical
Laboratories Inc. "If your compound annual growth rate is 55%, then
you have a neutral purchasing budget." That is, even though new
storage capacity is still expanding, storage prices typically
decline roughly 35% to 40% each year.
Best Practice No. 3: Include data classification and
migration features
Many older storage management tools stop at utilization and
capacity analysis -- omissions being corrected in newer products.
"It's dubbed 'SRM 2.0,' " says Stephen Foskett, director of data
practice at Contoural Inc., citing a proliferation of coming
products that examine file ownership, application relationships and
other requirements.
Once data is identified and classified, it is possible to match
storage resources with particular data types. Mission-critical data
types can reside on expensive high-performance storage, while
nonessential data types are placed on less expensive commodity
(near-line) storage. This is the premise behind tiered storage, and
it can have a profound impact on storage costs. Consider tools with
replication or migration features. Once a piece of data is
identified, such tools can automatically move that data to its
appropriate storage tier.
Best Practice No. 4: Replace older tools with heterogeneous
tools
Take every opportunity to reduce the number of storage
management tools in the enterprise. "A lot of companies are adding
storage [management functionality] to their enterprise management
tools," Foskett says. Having fewer tools will simplify the learning
curve for storage administrators, reduce licensing expenditures and
ease software maintenance tasks. However, storage administrators
must select a management tool that supports all (or most) of the
storage systems currently deployed. It's acceptable to use more
than one management tool where needed, but don't ignore the goal of
simplification.
Best Practice No. 5: Use data deduplication to maximize
storage efficiency
Data deduplication has attracted much
attention for its ability to eliminate redundant content.
Although deduplication is not yet a native feature of most
storage management tools, this "intelligent compression" has
become a vital part of archival or content addressed storage
(CAS) platforms. Data deduplication can provide levels of
compression up to 50 to 1.
Best Practice No. 6: Factor data retention into storage
growth and management
Data must also be kept for some prescribed period of time, which
varies by business and industry. Storage administrators must
account for retention in any capacity planning or management
activity, and capacity planning tools should in turn account for
that type of storage growth due to data retention. Similarly,
storage management tools should support and enforce retention
policies wherever possible. When data retention periods expire, the
management tool should also implement secure deletion to ensure
that unneeded data is eradicated as soon as possible.
Best Practice No. 7: Ensure adequate scalability for near and
long-term storage growth
Management tools must scale to accommodate hundreds of devices,
support dozens of operating system versions and operate across LAN,
WAN and SAN connections. Storage administrators must understand and
test the limits of scalability and decide when infrastructure
growth should justify a new software version or an entirely
different management product.
Best Practice No. 8: Storage management should include
virtualization
Server virtualization allows one physical server to host
numerous logical (virtual) machines; storage virtualization allows
various physical storage devices or systems to be treated as a
single ubiquitous storage resource. Both approaches improve
utilization and forestall new purchases. Storage management tools
should always include support for virtualization and popular
virtualization platforms. "Consider [management] tools that
natively support VMware," Foskett says. "They can tell you the
allocation of your storage LUNs, the virtual LUNs that VMware
instances are seeing, the virtual disks that they're using and
what's on them."