Taking FC SANs to the next level with clustered/scalable SANs

Enterprises are struggling with the increasing amount of data that they need to store, manage, and back up. Across industries, file formats are richer and file sizes are growing. With the rapid increase in data growth and capacity, the need for fast and secure access to data 365 days x 24 hours a day with no downtime becomes paramount.

Using scale-out or clustered storage is an advantageous way to respond to growth in a storage environment. The idea behind scale-out/clustered storage is straightforward. Instead of growing a storage system to its limits and then adding another separate storage system, scale-out/clustered storage provides a cluster of storage nodes that operates as a single entity. All storage controllers have physical limits to their expandability: the number of CPUs, memory slots, and space for disk shelves that dictate the maximum capacity and performance of which the controller is capable.

If more storage or performance capacity is needed, you might
be able to add CPUs and memory or install additional disk shelves,
but, ultimately, the storage controller will be maximized out. At
this stage, the only option is to acquire another controller and
scale up.
In a scale-up configuration, each additional controller is a completely independent management entity that does not provide shared storage resources. If the original controller is to be completely replaced by a newer and larger controller, data migration is required to transfer the data from the old to the new. This is time consuming and potentially disruptive, and likely requires configuration changes on all the attached host systems. If the new controller will coexist with the original controller, there are then two storage controllers to be individually managed and there are no built-in tools to balance or reassign workloads across them.

The situation becomes worse as the number of controllers increases. By using scale-up, the operational burden increases as the environment grows, and the end result is a very unbalanced and difficult-to-manage environment. Technology refresh cycles require substantial planning in advance, lengthy outages, and configuration changes, which will introduce risk into the system.

By contrast, using scale-out or clustering means that, as the storage environment grows, additional controllers are added seamlessly to the resource pool residing on a shared storage infrastructure. Host and client connections as well as datastores can move seamlessly and nondisruptively anywhere in the resource pool, so existing workloads can be easily balanced over the available resources and new workloads can be easily deployed.

Technology refreshes (replacing disk shelves, adding or completely replacing storage controllers) are accomplished while the environment remains online and serving data.

Although scale-out storage products have been available from
various vendors for some time, they typically have focused on technical and engineering applications in a NAS environment. Many vendors also offer clustered SAN or scalable SAN products. Enterprise applications such as Oracle®, SAP®, Microsoft® Exchange, SQL Server®, and SharePoint® (see Figure 1), for example, will benefit from the nondisruptive operation capabilities and seamless performance and capacity scaling with a clustered or scalable SAN.

Fibre Channel SANs are so prevalent with mission-critical environments that moving to a clustered SAN environment for a technology refresh, new data center build-out, or greenfield opportunity is a logical move for the following reasons.

Capacity for Scale
£ 12PB+ of capacity (example of a 6-node FC SAN)
£ 150+ I/O connections (example of a 6-node FC SAN)
Performance for Consolidation
£ >250K IOPS (example of a 6-node FC SAN)
Efficiency for Shared Infrastructure
£ Support for flash, deduplication, compression, thin provisioning
Designed for Multi-Tenancy
£ Logical storage containers for isolation
£ NPIV for virtualized fabrics
£ FC and FCoE support
Availability
£ Perform maintenance and upgrades without system downtime
£ Intra- and inter-cluster replication.

Fortunately, clustered SAN storage provides the ability to prevent outages from planned downtime (e.g. firmware upgrade, maintenance, adding controllers), and provide a highly scalable and highly available storage cluster.

To read more about Fibre Channel SANs, be sure to visit the Fibre Channel Industry Association website at: http://www.fibrechannel.org/.
The Fibre Channel Industry Association (FCIA) is a mutual benefit non-profit international organization of manufacturers, system integrators, developers, vendors, industry professionals and end users. The FCIA is committed to delivering a broad base of Fibre Channel infrastructure technology to support a wide array of applications within the mass storage and IT-based arenas. FCIA working groups and committees focus on specific aspects of the technology, targeting both vertical and horizontal markets including data storage, video, networking and storage area networking (SAN) management.