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Contd: IP Storage: Maximizing Investment
Interconnecting Fibre Channel SANs
Two IP storage-bridging protocols are available to provide the basis for interconnecting existing Fibre channel SAN environments. The use of IP networks here is typically to overcome the distance limitations of Fibre Channel; to provide lower cost solutions than using proprietary protocols over private fiber links; and to enable ubiquitous remote data protection and disaster recovery solutions.
FCIP is a TCP/IP-based tunneling protocol designed to transparently provide point-to-point connections between geographically distributed Fibre Channel SANs using FCIP gateways to connect to an IP network. It is particularly well suited to provide connectivity to remote SANs for backup and restore, or remote data replication applications.
iFCP is a TCP/IP-based protocol for interconnecting storage devices or Fibre Channel SANs using an IP infrastructure. IFCP solutions consist of Fibre Channel end-points connected to an IP network by means of iFCP gateways. It is particularly well suited to providing the reliable transport of storage data suited between separate SAN domains via TCP/IP LAN, MAN or W WAN infrastructure.
IP-Native SANs
In contrast, the iSCSI protocol enables the creation of complete SAN solutions based on Gigabit Ethernet, instead of Fibre Channel, network infrastructure. iSCSI is simply the combination of two very well-understood technologies: SCSI block storage commands running over a TCP/IP transport. The iSCSI protocol is an industry standard protocol (RFC 3720) created, maintained and ratified by the Internet Engineering Task Force (IETF).
iSCSI is interesting as a SAN alternative to direct-attached storage in environments where simplicity attached simplicity, flexibility, price/performance, and availability of administrative staff are critical IT decision factors, iSCSI SAN solutions (often called IPSANs) consist of iSCSI initiators (software driver or adapter) in the application servers, connected to iSCSI storage systems by means of standard Gigabit Ethernet switches and cables.
IP SANs are deployed for all the same reasons that Fibre Channel SANs are typically deployed as an alternative to direct attached storage.
According to IDC, the top reasons are:
Back: 46.0%
Storage consolidation: 40.0%
Satisfy on-going demands for additional capacity: 37.0%
Performance: 31.0%
Disaster recovery: 27.0%
New project or application deployment: 23.0%
Today backup and storage consolidation in the face of rapid, data growth are the primary reasons for considering an IP SAN, followed by the intention to implement an affordable disaster fordable recovery solution.
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