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Storage networks: Right size for SMBs? |
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By Randy Kerns
17 Sep 2004 | SearchCIO-Midmarket.com
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Storage has been traditionally attached directly to a server with a standard interface such as SCSI or Fibre Channel (FC). Separating the storage from the server to allow multiple servers to connect is not necessarily a storage network, but may be just resource sharing of the storage system. In a storage network, storage elements are connected to servers over a network in which different simultaneous connections are possible.
FC and Internet Protocol (IP) over Ethernet are the two types of connection technologies used in storage networking. Each type has some different characteristics, and it's important to determine which one may be required for an SMB .
FC is widely used in large enterprise data centers. In the small to midsize market, it has been used in prepackaged tools in which the FC switch, management and storage are all preconfigured in a rack and sold as a "SAN-in-a-box" solution. Newer, less expensive infrastructure products are changing the situation to allow VARs and systems integrators to provide custom solutions. From a storage networking standpoint, FC is an interface targeted at high performance for block-level I/O. It supports heterogeneous servers and storage with a nearly unlimited scaling of storage capacity and bandwidth.
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NAS is an attractive choice for SMBs that don't have storage professionals or other administrators with time to dedicate to storage.
Randy Kerns
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Ethernet with IP is used for two different storage networking approaches. One is for remote file serving with network-attached storage (NAS) and the other is for block I/O with iSCSI. Both of these approaches attempt to use existing Ethernet networks and switches, as well as network interface controllers, that are already installed in servers. In reality, many installations use a separate Ethernet network for storage because of data transfer demands.
NAS is used widely in workgroup and departmental environments and has been considerably successful in SMBs. It's also deployed more often in enterprise data centers, led by NAS gateway implementations. The most valued characteristics for NAS include the simplicity of administration and installation, as well as the very competitive cost structure. It literally takes minutes to install, and requires minimal administration. NAS is an attractive choice for SMBs that don't have storage professionals or other administrators with time to dedicate to storage.
Relatively new, iSCSI provides block I/O over the Ethernet infrastructure. Certain applications may either require or would be better served by block I/O than the file-based I/O provided with NAS. In these cases, SMBs should choose FC or iSCSI to provide the block I/O. Applications such as Microsoft Exchange and SQL would benefit from a block I/O solution like iSCSI.
Why storage networks?
There are many reasons that a storage network might make sense for an SMB. Certainly, one of the most obvious is that a storage network offers more bandwidth and accommodates data growth without affecting the environment. Here are some other reasons:
Data needs to be shared between applications on multiple servers. File-based data sharing is a basic capability of NAS. Block-based solutions allow the connection, but the sharing is the responsibility of the application and add-in software.
Resource utilization may be a problem. It may be that disk capacity is available in one server but desperately needed in another. With a storage network, you can manage the capacity more effectively. Tape drives or tape libaries are another resource that may be shared more efficiently. Connecting to a storage network allows more efficient use of tape resources.
Backup may be handled more effectively using the storage network for transfer of the data between devices. This may alleviate significant backup or availability problems.
You can implement some regulatory compliance procedures more easily by using specific storage devices connected in a network.
Most importantly, to determine if your SMB needs a storage network, you must understand your organization's business requirements. Once you've decided how to achieve those requirements, you might be able to determine if a storage network would be best for your SMB.
Randy Kerns is a senior partner with Evaluator Group in Greenwood Village, Colo. Randy focuses on storage networking, storage technologies, industry trends and futures, and company and product strategies.
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