Storage virtualization, Part 1 of 3: delivering non-disruptive operations, flexibility and simplified management

Computer Technology Review, Feb, 2005 by Mark Lewis

Today, the industry is abuzz with talk of storage virtualization. Expectations are being created around universal management of multi-vendor storage and various other promises to provide the answers to all of today's storage challenges. In an attempt to deliver on these expectations, there has been a lot of confusion, debate and rushed-to-market solutions.

Much of the discussion around storage virtualization centers on increasing the utilization of storage assets. Today's storage resource management tools allow users to monitor their entire storage infrastructure and proactively manage its utilization. While low utilization rates were deemed the unfortunate results of massive infrastructure build-outs during the post-Y2K bubble and maintaining high utilization remains an important best practice, IT managers have made tremendous progress in this area in the last few years. Asset utilization is a less pressing problem today and one for which many good solutions already exist.

Meanwhile, the data explosion has continued apace. The new view of data sees the data's value fluctuating, mandating different locations and different types of containers throughout its life. This gives a whole new meaning to the concept of data availability. For most organizations it means constructing complex IT infrastructures that can deliver the right information to the right place at the right time, 24 X 7. Today's businesses require continuous information availability and are unwilling and unable to endure large amounts of infrastructure downtime when delivering on the needs of the business.

Downtime costs can run into the hundreds of thousands or even millions of dollars per hour. From running a physically contained data center, we are rapidly moving to running IT operations as if they were a permanently earth-orbiting space station with in-flight fueling, maintenance and upgrades. IT managers have come to expect better tools for keeping their data continuously available.

Ten years ago, we asked, "what if we eliminated unplanned downtime?" Technologies such as application clustering and data replication tools such as EMC's SRDF have since succeeded in protecting data from outages in the case of hardware failures, disasters and other unpredictable events. With the right tools in place and with high levels of availability designed into new IT infrastructure projects, particularly for mission-critical applications, many data centers have succeeded in drastically minimizing their unplanned downtime.

But with the rapid increase in complexity of IT operations, the demand is also increasing for greater flexibility and responsiveness. IT has become critical in reducing delays in business processes and applications are now expected to be available 24 X 7 to more people than ever before, in more locations around the world.

So, today the question is, "what if we eliminated planned downtime?" Maintenance, application upgrades, physical changes to the infrastructure, data center migrations--they all reduce the time an application can be up and running. IT managers report that planned downtime accounts for between two-thirds and three-fourths of total downtime.

Specifically, IT managers who have networked their storage in recent years are now looking to:

* Move production data non-disruptively across the storage infrastructure without ever taking applications down. For instance, when introducing a new storage array into an existing SAN, a storage administrator would need to schedule this at a suitable time and ensure application owners are aware that data will be unavailable for a period of time. IT managers want to eliminate all storage-related downtime for any reason whatsoever.

* Centralize capacity allocation, provisioning and data movement capabilities in order to provide for more flexibility in multi-tiered, multi-vendor storage environments. To execute on ILM, for instance, if a volume in a medium performance storage pool is not meeting the specific service level guaranteed to the application owner, the storage administrator moves the data to a higher performing pool (most likely on a different tier of storage) to meet the requirement. In the future, we can envision this process being more automated based on policies set by the application owner.

More often than not, storage administrators today are handcuffed from making changes within the storage infrastructure. The business' intolerance for downtime, as well as the upstream impact on server and application administrators, stands in the way of everything from fine-tuning to much larger-scale moves and changes. If properly deployed, storage virtualization can give administrators the flexibility they need to make changes to the underlying infrastructure without impacting systems or applications.

These "Non-Disruptive Operations" mask the complexity of the IT infrastructure from the business user. Delivering this capability into today' storage infrastructures is the practical use case that will spur the broad acceptance and adoption of storage virtualization technology. But to be successful in achieving this new level of Non-Disruptive Operations, users must choose a storage virtualization solution that will not increase the complexity and cost of their storage infrastructure, while also retaining ease-of-deployment and protecting their existing investments in storage functionality.