What
is iSCSI
?
•IP based protocol used to connect host and storage
•IP based protocol used to connect host and storage
•Carries
block-level data over IP-based network
•Encapsulate
SCSI commands and transport as TCP/IP packet
Components of iSCSI
•iSCSI host initiators
–Host computer using a NIC or iSCSI HBA
to connect to storage
–iSCSI initiator software may need to be
installed
•iSCSI targets
–Storage array with embedded iSCSI
capable network port
• LAN
for IP storage network
–Interconnected Ethernet switches and/or
routers
iSCSI - Host Connectivity Options
•Three
options for iSCSI
configuration:
–Software Initiators
•Code that can be loaded onto a host to
provide the translation between the storage I/O calls and the network interface
–TCP Offload Engine (TOE)
•Moves the TCP processing load off the
host CPU onto the NIC card, to free up processing cycles for application
execution
–iSCSI HBA
•A network interface adapter with an
integrated SCSI ASIC (application-specific integrated circuit)
•Simplest option for boot from SAN
iSCSI Protocol Stack
iSCSI Protocol Stack
iSCSI Topologies
•Native
iSCSI
Connectivity
•No FC
components
•Each iSCSI
port on the array is configured with an IP address and port number
–iSCSI Initiators Connect directly to the Array
•Bridged
iSCSI
Connectivity
•Bridge
device translates iSCSI/IP to FCP
–Standalone device
–Integrated into FC switch (multi-protocol
router)
•iSCSI initiator/host configured with bridge as
target
•Bridge
generates virtual FC initiator
•Combining
FCP and Native iSCSI Connectivity
•Array
provides FC and iSCSI connectivity natively
•No
bridge devices needed