Managing storage through layers

V. VIVEKANAND on how storage area management solutions address many of the challenges that storage administrators face

IT IS apparent that information storage is regarded very highly among enterprises, as it has turned out to be a very potent tool for remaining competitive in today’s dynamic business environment. This has led to a tremendous explosion in demand for storage infrastructure. While the importance of storage is undeniably growing, enterprises are trying hard to transform storage from being seen as a cost component to one which enables the generation of more revenue. Even though the cost of raw storage is declining day by day, the prevalence of fibre channel technology in the networked storage era has led to a situation where the cost of manpower required to administer storage is constantly escalating. And with shrinking IT budgets, storage administrators are finding it increasingly difficult to meet the demands placed on them while they try to manage the storage infrastructure. This has become a deterrent factor for enterprises in their efforts towards transforming storage from a cost factor to a revenue enabler. The primary challenge here is therefore to manage the entire storage architecture, which, instead of having a small footprint, has a varied and heterogeneous footprint. This kind of situation puts the performance of business applications—and in turn the business—at risk.

Enter SAM

SAM (Storage Area Management) or consolidation of storage resources has apparently evolved as a viable solution for addressing these challenges. However, not all SAM solutions address all the challenges that storage administrators face. This is because, when considered from a business point of view, SAM is all about quality of service. In a typical organisation, storage administrators have to manually manage the various elements of the storage infrastructure, which may include file systems that are linked to the database, host bus adapters (HBAs), SAN Fabric switches, the host server, the storage system itself and the individual disk drive. The entire chain from drive to application has to be linked. This is a labour intensive, error-prone and slow process which adds to the delay and costs.

However, in today’s scenario, businesses that are able to deliver high levels of service easily will automatically reap benefits, whereas businesses that cannot will be in trouble. For instance, when an application experiences unexpected activity, it may not have sufficient storage to meet its requirement. Consequently, performance and service levels tend to deteriorate leading to crashes and downtime.

While the implementation of a SAM practice seems the most obvious solution in such a situation, it is important for administrators to recognise change and revisit the storage set-up. This is because if they have to effect change it has to be done not in months but in a matter of hours. They need to understand that the implementation of SAM should enable them to manage complex SAN infrastructure, storage resources to address process issues, and storage provisioning to enable new applications to come online quickly. In this manner the SAM solution should be able to deliver significant TCO improvements and faster ROI.

Layers within storage

However, in order to get the most out of a SAM implementation, it is important to follow a layered model for storage management, which the whole industry is slowly moving towards. This type of model relies on building layers within the storage infrastructure, and is based on the industry-wide standards initiative, CIM (Common Information Model). The model enables management systems to recognise and exchange information in a heterogeneous storage environment that houses different solutions from various vendors. CIM offers a powerful foundation for cross-platform SAM implementation. Though the industry has not reached a consensus on the exact definition of the layers, one model which has identified four basic management layers is slowly gaining prominence. The four layers comprise reporting, path management, event monitoring and automation control, and they are addressed in succession.

A strong foundation

However, all these four levels strongly depend on the base level—the discovery level—which serves as the building block for this model to work. This because, at the outset, organisations need to understand what storage resources they have and where they are. This is a very cumbersome process, which earlier used to comprise reams of spreadsheets, whiteboards and hand-written notes. Ideally, a good SAM solution should help administrators get a holistic perspective of all the elements involved in a storage infrastructure right from

the LUN (Logical Unit Number) all the way to the application. This has to be viewed from the application’s viewpoint. It helps administrators discover, track and locate existing resources and new resources that are being added to the storage infrastructure. This provides a logical platform that can be used to manage storage in a situation where enterprises prefer to build a storage infrastructure by sourcing from different vendors.

Once the storage administrator discovers all the elements within the storage system, it is important for him to understand how resources are being used. Why? Because to ensure that all mission-critical applications are functional, enterprises often resort to having buffer storage to meet unforeseen circumstances. However, automated reporting and monitoring to determine what additional resources are needed and when they are required comes out as a preferable approach. From this viewpoint, the SAM solution should be able to optimise existing storage resources rather than rely on buffer storage capacity to keep applications up and running. Ideally, while addressing the reporting level in storage management, the SAM solution should be able to provide an elemental overview across the entire storage infrastructure so that the company can continuously monitor storage from LUN to the application. Further, complementing the comprehensive reporting and monitoring functionality, the SAM solution should be able to provide administrators with predictive management tools based on historic data so that outages can be anticipated even before they happen and corrective actions can be taken. With such a reporting and monitoring system in place, administrators can optimise the use of existing resources and they can balance loads and shift excess capacity from one server and application to another. This eliminates the need for excess and unnecessary capacity, while existing excess capacity and bandwidth are available elsewhere within the infrastructure.

Manage that path

The next level after the reporting layer to be addressed is that of path management. The key to SAM is quality of service, and this is ensured through good path management. It is because one of the key aspects of path management is to monitor the flow of data from the storage resource to the application so as to ensure the application is receiving the required levels of service to perform optimally. Besides this, the path management function also entails provisioning of storage resources depending on the nature of the requirement. However, it is important to understand that this cannot happen unless the first two layers of discovery and reporting are in place.

Now that administrators have all the necessary data to help them understand storage resources, the ways to optimise storage, and the flow of data that is required to maintain different levels of service that different applications demand, they no longer need to struggle to understand the different fault and problem alerts that come their way. The data helps them exercise greater control, and initiate proactive measures to correct problems. This is the third layer in the storage environment where the SAM solution helps administrators troubleshoot problems easily and isolate components that need correction. This is enabled by the data flow alerts that the SAM solution sends to them periodically in relation to the applications’ service level requirements.

With the three layers in place, the last functionality the SAM solution should offer is to automate the entire management process using a policy-based management engine. For instance, when a critical application approaches a threshold signalling that the application will soon run short of storage space, the system acts automatically and allocates additional storage to that application. It lets the administrator be free of routine tasks so that he can focus on more important issues. At this level, organisations can fully leverage the SAM implementation to improve storage service quality while reducing costs.

While addressing these layers for management of storage, it is important to bind together these layers and populate them with the specialised management tools from different vendors. Therefore, the SAM solution should be one that leverages on the synergies of an open management framework and powerful intelligent storage systems. This requires a collaborative approach that can be achieved by developing strategic alliances to deliver SAM solutions that fit more into multi-vendor storage environments and are based on broad integration with third-party SAM software.

The author is sales director, SAM Solutions, APIA, Hitachi Data Systems. He may be contacted at vivek.anand@hds.com