iSCSI � What Does It Mean for Your Storage Network?
As the Internet and related activities continue to expand, the amount of data that needs to be stored is also increasing. Enterprises and other organizations require effective ways to store and maintain this data.
In recent years, many enterprises have seen a significant increase in the volume of data produced. And, this amount of data continues to increase, particularly in Web-based and e-Commerce environments. A good example would be e-mail which impacts worldwide storage by producing more data than is generated by new Web pages. These types of traffic are typically multimedia intensive. E-mail and Internet-related enterprise/commercial transactions combined have caused a dramatic increase in storable data moving across Internet Protocol (IP) networks.
A new method is needed to bring improved storage capabilities to IP networks and reduce limitations associated with Fibre Channel SANs. The solution, as is widely known, is Internet Small Computer Systems Interface (iSCSI) or SCSI over IP. But what does this new technology mean to your storage environment? This article will answer the following questions:
- What will iSCSI mean to your storage network?
- What will the upcoming availability of iSCSI mean to customers who perhaps had considered storage networking to be too expensive?
- What, in simple terms, will users need to implement an iSCSI based SAN?
- How will an iSCSI based SAN compare in terms of performance and cost to Fibre Channel?
What iSCSI Means to Your Storage Network
Internet SCSI (iSCSI) is a draft standard protocol for encapsulating SCSI command into Transmission Control Protocol/Internet Protocol (TCP/IP) packets and enabling I/O block data transport over IP networks. iSCSI can be used to build IP-based SANs. The simple, yet powerful technology can help provide a high-speed, low-cost, long-distance storage solution for Web sites, service providers, enterprises and other organizations.
An iSCSI Host Bus Adapter (HBA), or storage network interface card (NIC), connects storage resources over Ethernet. As a result, core transport layers can be managed using existing network management applications. High-level management activities of the iSCSI protocol (such as permissions, device information and configuration) can easily be layered over or built into these applications. For this reason, the deployment of interoperable, robust enterprise management solutions for iSCSI devices is expected to occur quickly.
First-generation iSCSI HBA performance is expected to be well suited for the workgroup or departmental storage requirements of medium- and large-sized enterprises. The availability of TCP/IP Offload Engines (TCP/IP Offload Engines (TOEs) are based on session-layer interface card (SLIC) technology, which can be used to improve the performance of servers, network-attached storage (NAS) and iSCSI storage devices.) will significantly improve the performance of iSCSI products. Performance comparable to Fibre Channel is expected when vendors begin shipping 10 Gigabit Ethernet iSCSI products in 2003.
Benefits of iSCSIBy combining SCSI, Ethernet and TCP/IP, iSCSI delivers the following key advantages:
- Builds on stable and familiar standards: Many IT staffs are familiar with the technologies.
- Creates a SAN with a reduced TCO: Installation and maintenance costs are low since the TCP/IP suite reduces the need for hiring specialized personnel.
- Ethernet transmissions can travel over the Global IP Network and therefore have no practical distance limitations.
- Provides a high degree of interoperability: Reduces disparate networks and cabling, and uses regular Ethernet switches instead of special Fibre Channel switches.
- Scales to 10 Gigabit : Comparable to OC-192 SONET (Synchronous Optical Network) rates in Metropolitan Area Networks (MANs) and Wide Area Networks (WANs).
Who Can Use iSCSI?
iSCSI SANs are most suitable for enterprises with a need for streaming data and/or large amounts of data to store and transmit over the network. This includes:
- Businesses and institutions with limited IT resources, infrastructure and budget. These organizations should look for iSCSI equipment that functions over standard Gigabit Ethernet Category-5 copper cabling already in place in most buildings today.
- For example, work team members who need the latest project data without waiting 24 hours for traditional replication/backup/reconciliation procedures.
- Geographically distributed organizations that require access to the same data on a real-time basis.
- Internet Service Providers (ISPs).
- Organizations that need remote data replication and disaster recovery. For example, a high-technology company in San Jose, California remains susceptible to disaster if it uses a Fibre Channel SAN. Original and backup data copies could be lost in the same earthquake due to distance limitations.
- Storage Service Providers (SSPs).