6.5.1

Table Of Contents
Configuring Advanced Parameters for iSCSI
You might need to configure additional parameters for your iSCSI initiators. For example, some iSCSI
storage systems require ARP (Address Resolution Protocol) redirection to move iSCSI traffic dynamically
from one port to another. In this case, you must activate the ARP redirection on your host.
The following table lists advanced iSCSI parameters that you can configure using the
vSphere Web Client. In addition, you can use the vSphere CLI commands to configure some of the
advanced parameters. For information, see the Getting Started with vSphere Command-Line Interfaces
documentation.
Important Do not change the advanced iSCSI settings unless VMware support or Storage Vendors
direct you to change them.
Table 115. Additional Parameters for iSCSI Initiators
Advanced Parameter Description Configurable On
Header Digest Increases data integrity. When the header digest parameter is enabled,
the system performs a checksum over each header part of the iSCSI
Protocol Data Unit (PDU). The system verifies the data using the
CRC32C algorithm.
Software iSCSI
Dependent Hardware
iSCSI
Data Digest Increases data integrity. When the data digest parameter is enabled, the
system performs a checksum over each PDU data part. The system
verifies the data using the CRC32C algorithm.
Note Systems that use the Intel Nehalem processors offload the iSCSI
digest calculations for software iSCSI. This offload helps to reduce the
impact on performance.
Software iSCSI
Dependent Hardware
iSCSI
Maximum Outstanding
R2T
Defines the R2T (Ready to Transfer) PDUs that can be in transition before
an acknowledge PDU is received.
Software iSCSI
Dependent Hardware
iSCSI
First Burst Length Specifies the maximum amount of unsolicited data an iSCSI initiator can
send to the target during the execution of a single SCSI command, in
bytes.
Software iSCSI
Dependent Hardware
iSCSI
Maximum Burst Length Maximum SCSI data payload in a Data-In or a solicited Data-Out iSCSI
sequence, in bytes.
Software iSCSI
Dependent Hardware
iSCSI
Maximum Receive Data
Segment Length
Maximum data segment length, in bytes, that can be received in an iSCSI
PDU.
Software iSCSI
Dependent Hardware
iSCSI
Session Recovery
Timeout
Specifies the amount of time, in seconds, that can lapse while a session
recovery is performed. If the timeout exceeds its limit, the iSCSI initiator
ends the session.
Software iSCSI
Dependent Hardware
iSCSI
No-Op Interval Specifies the time interval, in seconds, between NOP-Out requests sent
from your iSCSI initiator to an iSCSI target. The NOP-Out requests serve
as the ping mechanism to verify that a connection between the iSCSI
initiator and the iSCSI target is active.
Software iSCSI
Dependent Hardware
iSCSI
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