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Storage consolidation: SRM tools overview

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Storage consolidation isn't just a matter of hardware replacement. A consolidation strategy should also include software products that apply a layer of analysis and automation to the storage infrastructure.

Storage resource management (SRM) tools are an important part of storage consolidation. SRM tools allow storage administrators to see their storage environment, often across numerous platforms from a variety of vendors. SRM tools can organize and allocate the available storage, moving data between storage platforms or tiers as needed. SRM tools can also offer insights into future trends and growth by tracking the performance and utilization of storage resources.

Heterogeneity and interface

Even after a storage consolidation project is completed, an enterprise may rely on the availability of numerous storage systems for redundancy, tiered storage or sheer capacity. Software can then be applied to "see" and manage that storage. Many storage systems include their own unique management application, and that may be perfectly acceptable if your organization uses storage systems from a single vendor.

However, in a multivendor environment, an SRM tool must be able to automatically recognize diverse storage servers or arrays in the data center. Otherwise, some storage may remain underutilized. Worse, a storage administrator may have to deal with several tools to manage all of the available storage. It adds unnecessary complexity to a process that is intended to simplify storage.

The user interface is a key part of an SRM tool, especially when presenting storage from a variety of storage systems. Most SRM products tout a "single pane of glass" architecture that encompasses every storage device and allows users to quickly drill down for more comprehensive data or detailed information about specific storage systems.

Many SRM tools use agents installed on each system to be managed. Intelligent agents are often able to acquire more detailed information from each storage system. However, agents can also cause a slight performance hit in the production environment. And since agents are software, they need to be updated as the SRM software evolves (which adds more management complexity to the consolidated storage environment). Some SRM products use agentless data collection, but the granularity of collected data is not as fine.

Provisioning and migration

A big part of storage consolidation is the simplification of storage allocation -- seeing all of your available storage, then easily assigning storage to applications and users from available pools of data across the data center. SRM tools often include provisioning features that allow storage administrators to create, resize and manage LUNs. Once storage is allocated, data can be moved between locations or tiers.

Many storage organizations would rather not assign labor to manage tasks, like provisioning and migration, so automation is an important part of SRM tools. Provisioning and migration are often based on sets of user-defined rules. For example, if a mission-critical application runs short of storage, the SRM tool can allocate more space or move data to a larger space that had been prepared for it. Still, automation is not foolproof, and some amount of hands-on management will be required to ensure that key applications are running smoothly.

Tiering is perhaps the most common use of migration, moving older or lesser-used data to progressively lower tiers over time to free space on more expensive high-performance disks. Migration is also critical in hardware refreshes or consolidation tasks when data is moved from one system and placed onto another. Migration tasks will take time and have an impact on storage performance. In some cases, the impact is slight, and migration can be successfully accomplished in the background. However, moving large quantities of data in short timeframes will invariably affect storage performance -- potentially impacting service levels and application availability.

Planning and reporting

Even after a storage consolidation has been completed, storage demands will continue to grow. If a storage administrator does not manage this growth proactively, application availability and performance may take a hit, forcing the organization to "fight fires" by adding storage without adequate planning or budgeting. Most SRM tools include monitoring features that can report on storage or application performance. The tools alert administrators when potentially dangerous performance thresholds are reached, reducing the possibility of server or application crashes due to low storage.

SRM tools collect and digest storage utilization and performance data over time to provide trend analysis and reporting that can help administrators make savvy purchase decisions (rather than react to unexpected service problems). By understanding when and where storage will be needed in the future, a storage organization can budget accordingly and take advantage of declining storage hardware costs over time. Reliable trend analysis can allow an organization to purchase larger disks at a lower cost tomorrow rather than stockpiling smaller, more expensive disks today. Predictive reporting can also help to schedule regular maintenance, repairs and pre-emptive device replacement.

18 Jan 2008