Listing and Setting iSCSI Parameters with ESXCLI

You can list and set iSCSI parameters for software iSCSI and for dependent hardware iSCSI by using ESXCLI.

You can retrieve and set iSCSI parameters by running one of the following commands.

Parameter Type	Command
Adapter-level parameters	esxcli iscsi adapter param set --adapter=<vmhba> --key=<key> --value=<value>
Target-level parameters	esxcli iscsi adapter target portal param set --adapter=<vmhba> --key=<key> --value=<value> --address=<address> --name=<iqn.name>
Discovery-level parameters	esxcli iscsi adapter discovery sendtarget param set --adapter=<vmhba> --key=<key> --value=<value> --address=<address>

Parameter Type

Command

Adapter-level parameters

esxcli iscsi adapter param set --adapter=<vmhba> --key=<key> --value=<value>

Target-level parameters

esxcli iscsi adapter target portal param set --adapter=<vmhba> --key=<key> --value=<value> --address=<address> --name=<iqn.name>

Discovery-level parameters

esxcli iscsi adapter discovery sendtarget param set --adapter=<vmhba> --key=<key> --value=<value> --address=<address>

The following table lists all settable parameters. These parameters are also described in the IETF rfc 3720. You can run esxcli iscsi adapter param get to determine whether a parameter is settable or not.

The parameters in the table apply to software iSCSI and dependent hardware iSCSI.

Table 1. Settable iSCSI Parameters
Parameter	Description
`DataDigestType`	Increases data integrity. When data digest is enabled, the system performs a checksum over each PDUs data part and verifies using the CRC32C algorithm. Note: Systems that use Intel Nehalem processors offload the iSCSI digest calculations for software iSCSI, thus reducing the impact on performance. Valid values are `digestProhibited`, `digestDiscouraged`, `digestPreferred`, or `digestRequired`.
`HeaderDigest`	Increases data integrity. When header digest is enabled, the system performs a checksum over the header part of each iSCSI Protocol Data Unit (PDU) and verifies using the CRC32C algorithm.
`MaxOutstandingR2T`	Max Outstanding R2T defines the Ready to Transfer (R2T) PDUs that can be in transition before an acknowledgement PDU is received.
`FirstBurstLength`	Maximum amount of unsolicited data an iSCSI initiator can send to the target during the execution of a single SCSI command, in bytes.
`MaxBurstLength`	Maximum SCSI data payload in a Data-In or a solicited Data-Out iSCSI sequence, in bytes.
`MaxRecvDataSegLen`	Maximum data segment length, in bytes, that can be received in an iSCSI PDU.
`NoopOutInterval`	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. Supported only at the initiator level.
`NoopOutTimeout`	Amount of time, in seconds, that can lapse before your host receives a NOP-In message. The message is sent by the iSCSI target in response to the NOP-Out request. When the `NoopTimeout` limit is exceeded, the initiator terminates the current session and starts a new one. Supported only at the initiator level.
`RecoveryTimeout`	Amount of time, in seconds, that can lapse while a session recovery is performed. If the timeout exceeds its limit, the iSCSI initiator terminates the session.
`DelayedAck`	Allows systems to delay acknowledgment of received data packets.

You can use the following ESXCLI commands to list parameter options.

Run esxcli iscsi adapter param get to list parameter options for the iSCSI adapter.
Run esxcli iscsi adapter discovery sendtarget param get or esxcli iscsi adapter target portal param set to retrieve information about iSCSI parameters and whether they are settable.
Run esxcli iscsi adapter discovery sendtarget param get or esxcli iscsi adapter target portal param set to set iSCSI parameter options.

If special characters are in the <name>=<value> sequence, for example, if you add a space, you must surround the sequence with double quotes ("<name> = <value>").