Most of us have overheard the term “storage” and understand it to be technology that allows us to store electronic documents. Sounds a lot like a hard drive, right? Yes, but, unfortunately the definition is not that simple. This frequently overheard term is generally used in reference to one of a variety of types of storage. More often than not, the type of storage referred to pertains to Direct Attached Storage (DAS), Network Attached Storage (NAS) or a Storage Area Network (SAN).
The focus of this article is on SANs, which are designed to share high-speed storage (hard disks) between multiple servers, each connected by a high speed interface, allowing them to cooperatively share the storage. SANs are very versatile in the ways in which they can be leveraged to increase availability (data center “up time”), server performance and IT support efficiency, while also lowering total cost of ownership (TCO) and complexity.
Some of the more prominent benefits of an effectively implemented SAN include:
- The ability to more effectively leverage unused disk space.
- Increased storage processing speed.
- Improved performance of attached servers.
- Enhanced data integrity and storage reliability.
- Storage space can be easily expanded when needed; assuming anticipated capacity needs were accurately accounted for prior to purchase.
- Optimal storage utilization through de-duplication, resulting in less space requirements for the same data.
- Snapshot capabilities. This is a revolutionary innovation that allows for instantaneous, point-in-time backups to disk of application databases, such as Oracle, Microsoft Exchange, SQL Server, etc.
Selection Considerations
Unfortunately there are a few technical variables that cannot be ignored when selecting a SAN. Some of these create consternation for those trying to decide which vendors’ product will represent the best cost/benefit solution for the bank?
Two prevalent options for connecting to a SAN are iSCSI and Fibre Channel. Fibre Channel provides for a faster link than iSCSI, but, Fibre Channel is more expensive, more complex and prone to more compatibility issues than iSCSI. Also, most of the more common types of servers found in banks, those that are Intel processor based, cannot take advantage of the bandwidth gains of Fibre Channel, making it irrelevant. Also, processes per second are quite similar between the two, again rendering iSCSI the more logical choice for the majority.
There are different types of drives that can be used within a SAN. Sometimes multiple types are utilized as part of a tiered storage configuration. Generically speaking, the faster the speed of the hard drive, the more expensive it is. Highly reliable, fast drives commonly found in SANs are SAS drives. Alternatively, SATA drives, also highly reliable, cost less, but are not as fast. Why the dilemma? Some types of data, typically archived files, are less frequently accessed and do not require the performance level of system or database files. Perhaps within your bank there is a large volume infrequently accessed, archive data. It may make economical sense to purchase fewer SAS drives, yet also have SATA drives dedicated to this type of data.
Make certain to go with an innovative, industry leading SAN manufacturer having effective partnerships with common, market leading manufacturers of complimentary products.
The Benefits of Integrating SAN with Server Virtualization
When server virtualization is effectively combined with the correct SAN technology, as not all are created equal, the benefits begin to resemble true synergy.
The integrated SAN/Server Virtualization solution results in reduced planned and unplanned downtime. A few of the capabilities, if configured, can include:
- Automatic restart of virtual servers on different hardware, if a physical server fails.
- Automatic move of virtual servers to another physical server, if a virtual member is abnormally demanding more resources.
- IT staff can perform a live migration of virtual servers from one physical server to another, enabling hardware maintenance to occur during business hours versus having to wait until after hours.
- Data deduplication can dramatically reduce backup times and can be used by two SAN devices in an effectively configured virtual server environment to efficiently replicate systems and data off-site for true business survivability.
Dean Lemons is a managing director with RSM McGladrey. For more information, contact him at dean.lemons@rsmi.com.
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