By Mike Reynolds published: Friday, January 25 2008
Virtualization technology is transforming the data center. After all, IT organizations have never been faced with so many challenges—from exponential storage growth to increasing operational costs, power and cooling limitations, and the need to provision and quickly bring new business-critical applications online. The introduction of virtualization into the data center promises to ease such management burdens while delivering bottom-line results.
However, as organizations adopt storage and server virtualization strategies, they are discovering that monitoring, reporting, and managing such an environment actually increases the complexities of storage management. Indeed, even in a physical environment, storage management has been challenging as administrators continue to struggle with scripts and spreadsheets in an effort to understand the resources upon which business-critical applications depend. And in a virtual environment, wherein physical storage is now separated by two or more degrees from the application, the inadequacy of such manual approaches quickly becomes evident.
Storage resource management (SRM) technology addresses the demands and management complexities that virtualization presents. With SRM, IT can decompose logical storage through the virtualization layer all the way back to one or more physical resources, including SAN connectivity, thereby easing storage management in the virtual enterprise.
A Virtual Shift
Storage virtualization abstracts storage, separating logical data access from physical access. It offers a bridge between one or more physical storage arrays through one or more storage virtualization methods that present logical elements to a host. Typically, storage virtualization employs a virtual logical unit number (vLUN) to mask its back-end physical complexity. Then, regardless of whether the storage originated from one or many devices, it is delivered as though it originated from a single device.
The trouble is, traditional storage management solutions can no longer see the entire data path, from application to storage. Nonetheless, storage administrators require deeper visibility of the entire path—from virtualized host(s) to the virtual storage—as well as the capability to map the virtual storage to the physical storage devices. Moreover, few have the tools to correlate the outage of a back-end array LUN that sits behind a storage virtualization appliance to its potential impact on a business application.
Management complexities also arise from server virtualization approaches to delivering application services. These approaches run virtual machines on a hypervisor to increase the physical server utilization of an individual entity. Yet, this additional layer of abstraction makes effective storage management impossible using traditional storage management solutions that see only the physical server and have no insight into the applications running on virtual servers.
Visibility and Mapping
A proper SRM solution provides the capability to manage heterogeneous physical and virtual storage environments. When instrumented properly, SRM tools provide full discovery and visibility, end-to-end resource mapping, monitoring, alerting, and reporting of virtual, logical and physical storage. The information collected by the SRM solution is critical not only for managing accurate capacity allocation and utilization levels, but also for providing root cause analysis to pinpoint the location of a potential interrupt that might impact application performance or cause an outage.
A suitable SRM solution will decompose the entire physical data path, thereby providing a comprehensive view into the characteristics and configurations related to heterogeneous storage devices. For example, SRM discovers and maps array ports, LUNs and the ports to which they are bound, as well as LUN attributes such as capacity, host masking tables, and physical disks that are unused or are associated with a LUN.
In addition, a SRM solution recognizes SAN connectivity and storage that may be directly attached to a host and, therefore, provides a complete view from the array ports, outbound, into and out of the SAN switch, and continuing to the HBA port at the host. Bandwidth will also be monitored from the HBA to the physical disk, and the reporting capabilities of SRM help detect traffic bottlenecks and provide metrics that may impact storage delivery to the host and the applications it supports.
Because the complexity of a storage network may result in undetected problems and changes, an adequate SRM solution will provide continuous monitoring that offers visibility into the health of every major storage component. Administrators will be proactively alerted on intermittent errors, failures, and environmental conditions such as battery states and temperature so they will be able to maintain the operational readiness of their storage environment. A proper SRM solution will also track and measure statistics to help determine loads and potential configuration issues that might impact performance.
SRM solutions also deliver deep levels of visibility, reporting, and management for virtual host applications. SRM offers automatic resource association mapping for guest operating systems to a virtual server as well as discovery and mapping of storage pool capacities and allocation to guests. With a SRM solution properly deployed, administrators can understand which applications are running on virtual machines, when those virtual machines are moved from one physical server to another, and what storage resources are being consumed by each application, whether physical or virtual.
Strategy for Success
By implementing virtualization strategies, organizations will be able to control costs for space power and cooling. However, as data volumes grow, managing storage will become even more complex in the virtualized environment.
To maximize the potential benefits of virtualization, organizations must also implement the appropriate SRM tools to help overcome new challenges that virtualization introduces in the storage realm. Traditional approaches fall exceedingly short, particularly in virtualized environments, driving organizations to deploy more comprehensive storage management strategies. Furthermore, the storage and server management solutions businesses deploy must provide the same levels of support to virtualized storage as they do for classic physical storage.
With the ability to decompose logical storage through the virtualization layer, SRM enables organizations to master storage complexity and seamlessly manage storage resources in both physical and virtual environments. As a result, organizations can more easily manage storage resources, drive up utilization rates, quickly identify and resolve potential problems, and ultimately maintain application service levels.
As a Symantec product marketing manager, Mike Reynolds oversees all go-to-market activities of the Veritas CommandCentral solution. Prior to Symantec, Mike spent more than 10 years working in the storage industry, including roles in the hardware and services arenas.
