6.5.1

Table Of Contents
iSCSI Session Management
To communicate with each other, iSCSI initiators and targets establish iSCSI sessions. You can review
and manage iSCSI sessions using vSphere CLI.
By default, software iSCSI and dependent hardware iSCSI initiators start one iSCSI session between
each initiator port and each target port. If your iSCSI initiator or target has more than one port, your host
can have multiple sessions established. The default number of sessions for each target equals the
number of ports on the iSCSI adapter times the number of target ports.
Using vSphere CLI, you can display all current sessions to analyze and debug them. To create more
paths to storage systems, you can increase the default number of sessions by duplicating existing
sessions between the iSCSI adapter and target ports.
You can also establish a session to a specific target port. This capability is useful if your host connects to
a single-port storage system that presents only one target port to your initiator. The system then redirects
additional sessions to a different target port. Establishing a new session between your iSCSI initiator and
another target port creates an additional path to the storage system.
The following considerations apply to iSCSI session management:
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Some storage systems do not support multiple sessions from the same initiator name or endpoint.
Attempts to create multiple sessions to such targets can result in an unpredictable behavior of your
iSCSI environment.
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Storage vendors can provide automatic session managers. Using the automatic session manages to
add or delete sessions, does not guarantee lasting results and can interfere with the storage
performance.
Review iSCSI Sessions
Use the vCLI command to display iSCSI sessions between an iSCSI adapter and a storage system.
In the procedure, --server=server_name specifies the target server. The specified target server
prompts you for a user name and password. Other connection options, such as a configuration file or
session file, are supported. For a list of connection options, see Getting Started with vSphere Command-
Line Interfaces.
Prerequisites
Install vCLI or deploy the vSphere Management Assistant (vMA) virtual machine. See Getting Started with
vSphere Command-Line Interfaces. For troubleshooting, run esxcli commands in the ESXi Shell.
vSphere Storage
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