Prerequisites for Implementing Storage SLA

By CIOReview | Tuesday, May 23, 2017
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Typically, Service Level Agreements (SLA) are types of contract that contain service-level descriptions which are used to create, arrange laws or rules into a systematic code with respect to storage efficiency. Ideally SLAs are legal fictions created in contracts that set goals or minimum requirements for the contracted vendor for delivery of services, from a consumer's perspective. In principle, these statements are intended in ensuring that vendors interpret the needs properly and possess the capabilities to deliver the required services and to reassure consumers about the same. However, sometimes in order to provide the basis for exiting the arrangement, the specifications of service levels are incorporated. Some outsourcing vendors complain that by establishing impossible service delivery expectations and inflexible methods for remediating missed goals, a storage SLA can enable contract failure. This often guarantees the dissolution of the agreement on the first occasion of a missed service level.

A storage SLA can be established between a company and a third-party vendor such as a cloud or outsourcing service provider or between the firm and its internal IT department regardless of the intent. A perfect mix of measured outcomes and general targets can be used to form a storage SLA.

Although SLA details can vary from business to business but, a contract covering at least following six areas will help both companies and providers meet their service goals:

Storage Capacity: The amount of storage available to the company and its users and applications at any given time is generally specified by the storage SLA. As the objective is to ensure that applications don't run out of room for storing their data, there are various principles that follow. If thin provisioning technology is used, the forecasting algorithms used in calculating capacity reserves may be specified to provide both for forecast-able storage demand and non-forecast-able "margin call" events.

System Performance: Accurate measurements of application workload output determine the performance of good service-level standards, separating from the performance of storage gear itself. For a better performance, we should also consider non-storage related performance inhibitors such as interconnect issues, protocol issues or application software problems. Storage performance requirements such as the number of transactions stored per hour in an accounting system, or in terms of IOPS or bytes per minute may be specified using metrics dictated by the application using the gear.

Efficient Allocation: With the proper provisioning and balance between resources and services occurring within a specified period of time, storage needs to be allocated efficiently to workloads. Defining agility in IT operations—an organization’s IT teams need to streamline the sharing of storage resources processes with the applications or end users.

Utilization efficiency: Utilization efficiency is often overlooked, even though it plays a key role in running an efficient storage operation. This level is a measure of effective data assignment towards infrastructure components based on the data value, the frequency of access, and the capabilities and cost of the storage itself. In a tiered storage environment, this is an assessment of the methodology or algorithms used by the hierarchical storage management software, which—as the data ages and reference frequency declines. This feature moves data from expensive, high-performance tiers to less expensive, high-capacity tiers.

Up Time: It specifies the total number of units of downtime permitted within a measured time frame. The greater the number of nines in the fraction, the lower the amount of downtime expected. Storage that supports always-on application workloads will likely be configured into active-active clusters to provide zero downtime.

Security: Based on business criticality and regulatory requirements, various data protection service levels align with the requirements of data itself will be established in the SLA. Commonly, these levels include synchronous replication for full and uninterrupted access to data. This is provided by two or more storage components: asynchronous replication for continuous access to most data, and tape backup for access to most data within a specified timeframe. Additional service levels may specify strategies for continuous data protection that could be lost in the event of an interruption.