Справочник Пользователя для IBM Flex System V7000 Expansion Enclosure 4939H29
Модели
4939H29
Chapter 11. SAN Connections and Configuration
435
Draft Document for Review January 29, 2013 12:52 pm
8068ch11-SAN Config.fm
Figure 11-2 SAN Connectivity within the IBM Flex System Enterprise Chassis
11.3 iSCSI Connectivity
The Internet Small Computer System Interface (iSCSI) protocol is the encapsulation of the
industry standard SCSI protocol within TCP/IP packets. The iSCSI protocol provides a
block-level storage capability similar to Fibre Channel (FC) storage area network (SAN)
technology. This is essentially the same system of encapsulating the SCSI protocol within an
external “carrier.” The difference is that the iSCSI SAN uses Ethernet instead of FC transport
technology. The iSCSI protocol uses TCP to transport SCSI I/O commands over a network. It
provides block-level data access where it encapsulates SCSI commands into protocol data
units (PDUs) within the TCP/IP protocol, and then transports them over the network to the
target device.
industry standard SCSI protocol within TCP/IP packets. The iSCSI protocol provides a
block-level storage capability similar to Fibre Channel (FC) storage area network (SAN)
technology. This is essentially the same system of encapsulating the SCSI protocol within an
external “carrier.” The difference is that the iSCSI SAN uses Ethernet instead of FC transport
technology. The iSCSI protocol uses TCP to transport SCSI I/O commands over a network. It
provides block-level data access where it encapsulates SCSI commands into protocol data
units (PDUs) within the TCP/IP protocol, and then transports them over the network to the
target device.
iSCSI transactions occur between an iSCSI initiator (hardware or software) that transmits a
request (such as read/write) and an iSCSI target. This iSCSI target processes the request
and responds with the appropriate information, such as data and sense. The initiating device
in the Flex System environment is the compute node and the target devices are the IBM Flex
System V7000 Storage Node canisters. The connectivity between the initiator and target is
shown in Figure 11-1 on page 434 and detailed in that section. The type of connectivity would
be determined also by the compute node platform, operating system and its device drivers.
request (such as read/write) and an iSCSI target. This iSCSI target processes the request
and responds with the appropriate information, such as data and sense. The initiating device
in the Flex System environment is the compute node and the target devices are the IBM Flex
System V7000 Storage Node canisters. The connectivity between the initiator and target is
shown in Figure 11-1 on page 434 and detailed in that section. The type of connectivity would
be determined also by the compute node platform, operating system and its device drivers.
11.3.1 Session establishment and management
A
session
is the creation of a communication tunnel from the iSCSI initiator to the iSCSI
target. An iSCSI session consists of an
iSCSI login phase
and a
full feature phase
. At least
one session between the initiator and the target must be enabled through an iSCSI login
process. A login protocol data unit (PDU) is used to negotiate any variable parameters
between the two parties and can start a security routine to authenticate permissible
connectivity. When the login is successful, the target issues a login success to the initiator.
process. A login protocol data unit (PDU) is used to negotiate any variable parameters
between the two parties and can start a security routine to authenticate permissible
connectivity. When the login is successful, the target issues a login success to the initiator.