.SAN design reference guide Vol. 1-5 785350-001

19 iSCSI storage
This chapter describes iSCSI storage in an HP SAN environment:
• “iSCSI overview” (page 318)
• “iSCSI concepts” (page 318)
• “iSCSI storage network requirements” (page 322)
• “HP Native iSCSI products” (page 322)
• “HP iSCSI bridge products” (page 332)
iSCSI overview
iSCSI is a storage transport protocol. The IETF developed iSCSI to encapsulate the SCSI protocol
over an IP network. iSCSI has many of the same mechanisms as the Parallel SCSI and Fibre Channel
protocols.
iSCSI facilitates creating SANs that include IP technology. iSCSI establishes and manages
connections between IP-based hosts and storage systems. Many Fibre Channel switches and routers,
as well as NAS systems, provide iSCSI support.
This section describes the following topics:
• “iSCSI and Fibre Channel” (page 318)
• “iSCSI bridge to Fibre Channel” (page 332)
iSCSI provides access to storage systems and SANs over standard Ethernet-based TCP/IP networks
that can be dedicated to storage or in some cases, shared with traditional Ethernet applications.
NOTE: Existing TCP/IP networks might not support iSCSI storage. HP recommends using a
dedicated Gigabit Ethernet network between iSCSI initiators and targets. This ensures adequate
data security and performance. As an alternative, use IPsec to secure the connection on a public
network with decreased performance. See the specific HP product requirements to determine if a
dedicated IP network for storage is required.
iSCSI and Fibre Channel
There are many factors to consider in choosing iSCSI or Fibre Channel, including:
• Lower deployment costs for iSCSI compared to Fibre Channel
• Widespread knowledge of IP technology for iSCSI
• Less expensive IP components
• iSCSI support for many server models
• Open architecture design with iSCSI
• iSCSI performance well matched to small and mid-range storage applications
iSCSI concepts
This section describes key iSCSI concepts:
• “Initiator and target devices” (page 319)
• “iSCSI naming” (page 319)
• “Discovery mechanisms” (page 319)
• “Sessions and logins” (page 320)
• “Security” (page 321)
318 iSCSI storage