iSCSI in a virtualized world: architecture can provide flexibility, scalability, high availability, reliability and performance

Communications News, Dec, 2008 by Larry Cormier

Virtualization technologies are changing the way organizations deploy server, networking and storage resources. These new architectures are more flexible and require organizations to provision storage resources quickly and easily in an effort to meet dynamic demand.

In the past, organizations were likely to deploy static, inflexible, homogeneous storage environments, typically tapping a single vendor to provide Fibre Channel storage area networks (SANs). Often, manageability was viewed as an add-on, a throw-in that a storage vendor provided for a nominal fee and sometimes for free. Complexity throughout the shared storage environment was accepted, countered only through advanced training and by expensive consultants.

In the past several years, IP storage has gained traction among large and small organizations alike, mainly due to its scalable and increasingly high-performing architecture. While in the past, Internet small computer system interface (iSCSI) was seen as low-end, bare-bones storage that was better suited for small, non-mission-critical environments, the availability of next-generation storage products has simplified complex administration, while offering new capabilities like non-disruptive scalable performance.

The iSCSI architecture can align storage environments in virtualization technologies. These environments need additional flexibility, scalability, high availability, reliability and performance, iSCSI allows IT to quickly provision storage resources, integrates shared storage with virtual server environments, and enables flexible and dynamic business models.

Leading iSCSI SAN solutions allow organizations to take advantage of existing infrastructure to deploy reliable, scalable and efficient multisite SANs. The performance increases over the past several years make delivering data quickly across large distances possible--without degrading performance. While resources may be distributed, management remains consolidated through a centralized console, giving administrators the flexibility to deliver storage wherever and whenever the business dictates.

Multisite iSCSI SANs provide built-in redundancy and failover capabilities, protecting the business from regional disasters or data center outages. For example, if a storage node is unavailable, the infrastructure is already in place to redirect the traffic load to available resources--whether volumes are stored on campus or across geographies. When business growth requires additional capacity, nodes can be provisioned quickly using iSCSI, making it available to applications and end-users.

iSCSI also enables processing power and bandwidth to be scaled in accordance with capacity. Some iSCSI storage vendors allow customers to build SANs from clusters of storage nodes, where each node includes RAM, memory and its own network ports and disk drives, making sure these resources are not taken away from existing nodes.

iSCSI SANs can also increase utilization. With IP storage solutions that save data over the entire cluster, capacity is balanced between nodes, ensuring that part of the system is not overloaded while other nodes remain underutilized. This capability helps eliminate single points of failure, allowing data to automatically failover between nodes in case of planned or unplanned downtime.

The modular design of iSCSI SANs gives administrators the ability to add, administer and replace nodes quickly and without having to take systems off-line or otherwise affect end-user productivity. This extends the flexibility of the server network to the storage realm, optimizing the entire IT infrastructure for end-to-end virtualization solutions.

iSCSI also can extend virtualization capabilities throughout the data center and beyond, without compromising the high-level advanced features.

Larry Cormier is vice president of marketing for LeftHand Networks, Boulder, Colo.