Ok, so you’re a CIO or CTO and have decided to purchase that spanking new, shiny server. You smile politely at the vendor until they mention storage. As the vendor starts to go into the benefits of Storage Area Networks (SAN) and Network Attached Storage (NAS), you can feel your eyes starting to glass over, your mind going blank and your smile becoming fixed as you get lost in the maze of acronyms and explanations of what type of storage would be best for you.
Storage has also recently become sexy and important in the enterprise market. Its relative importance has grown to new levels for IT managers. Companies that can effectively manage large amounts of data and make them readily available will have a significant competitive advantage over companies that can't.
Although each targets different market segments, there is potential for overlap as NAS technology improves. NAS generally captures the low-end to midrange market; SANs are more often found in the high-end side of things. Before you can really make a valued judgment as to which type of storage is best for you and your company, an understanding of each is important.
Storage Area Networks
Storage Area Network (SAN) is a high-speed network or subnetwork of shared storage devices. These storage devices interconnect different kinds of data storage devices with associated data servers on behalf of a larger network of users.
SAN architecture works in a way that makes all storage devices available to all servers on a Local Area Network (LAN) or Wide Area Network (WAN). As more storage devices are added to a SAN, they too will be accessible from any server in the larger network.
SANs use optical fiber or Fiber Channel technology to communicate. It has been likened to the common storage bus (flow of data) in a personal computer that is shared by different kinds of storage devices such as a hard disk or a CD-ROM player.
SANs support disk mirroring, backup and restore, archival and retrieval of archived data, data migration from one storage device to another, and the sharing of data among different servers in a network.
Many of the key players in the SAN market are those … surprise, surprise, key players in the enterprise server market. Vendors like IBM, Hewlett- Packard etc, have silos for storage in different countries where they host storage for clients.
Network Attached Storage
NAS is hard disk storage or server that is set up with its own network address rather than being attached to the department computer that is serving applications to a network's workstation users. NAS does not provide any of the activities that a server in a server-centric system typically provides, such as e-mail, authentication or file management. By removing such management, both application programming and files can be served faster because they are not competing for the same processor resources.
NAS is a good solution for general-purpose storage services from low-end clients to high-performance servers as it communicates through IP protocols so it doesn't require expensive host bus adapters, which are required for Fiber Channel. NAS devices found in enterprise-class systems have been useful as content caching appliances for static content and streaming media, as well as some high-performance file serving. Typically though, high-end databases and server clusters primarily use SANs for their storage needs.
Companies like EMC and Hitachi Data Systems are making large gains in this market. They are becoming well known for their reliability and constant updating and revisions to their lineup.
The shape of things to come
iSCSI, the IP networking community's answer to Fiber Channel for storage networking, will be an important protocol for IT managers to learn and implement soon. iSCSI’s transport protocol allows SCSI commands to travel through IP networks, which will allow IT managers to use high-speed IP networking technology such as routers, switches and Gigabit Ethernet to carry data from storage units to servers anywhere throughout a corporate network. iSCSI was developed by IBM research and Cisco and is expected to be ratified by the Internet Engineering Task Force (IETF) storage standards body soon.
IBM hopes that iSCSI will centralize storage management and provide non-disruptive growth for high performance database and transaction servers.
You need to know more
Once you have a basic idea of what you want, your decision making process still continues. You have to decide on levels of scalability, stability, vendor reliability and possible outsourcing of skills. Each is as important as the type of storage used and deserves as much attention