How to Enable Multiple iSCSI Sessions for a Target

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You can use this procedure to create multiple iSCSI sessions that connect to a single target. This scenario is useful with iSCSI target devices that support login redirection or have multiple target portals in the same target portal group. Use iSCSI multiple sessions per target with the SCSI Multipathing (MPxIO) feature of Oracle Solaris. You can also achieve higher bandwidth if you utilize multiple NICs on the host side to connect to multiple portals on the same target.

The MS/T feature creates two or more sessions on the target by varying the initiator's session ID (ISID). Enabling this feature creates two SCSI layer paths on the network so that multiple targets are exposed through the iSCSI layer to the Oracle Solaris I/O layer. The MPxIO driver handles the reservations across these paths.

For more information about how iSCSI interacts with MPxIO paths, see Setting Up iSCSI Multipathed Devices in Oracle Solaris.

Review the following items before configuring multiple sessions for an iSCSI target:

A typical MS/T configuration has two or more configured-sessions.
However, if your storage supports multiple TPGTs and if you are using the SendTarget discovery method on your host system, then the number of configured sessions can be set to 1. SendTarget discovery automatically detects the existence of multiple paths, and multiple target sessions are created.
Confirm that the mxpio configuration parameter is enabled in the /etc/driver/drv/iscsi.conf file.
```
# cd /etc/driver/drv
# grep mpxio iscsi.conf iscsi.conf
iscsi.conf:mpxio-disable="no";
```
Confirm that the multiple network connections are configured by using IPMP.
Confirm that the multiple network connections are available.
```
# ipadm show-addr
```

Become an administrator.

List the current parameter values for the iSCSI initiator and the target.

List the current parameter values for the iSCSI initiator.

initiator# iscsiadm list initiator-node
Initiator node name: iqn.1986-03.com.sun:01:0003ba4d233b.425c293c
Initiator node alias: zzr1200
        .
        .
        .
        Configured Sessions: 1

List the current parameter values for the iSCSI target device.

initiator# iscsiadm list target-param -v iqn.1992-08.com.abcstorage:sn.84186266
Target: iqn.1992-08.com.abcstorage:sn.84186266
        Alias: -
        .
        .
        .
        Configured Sessions: 1

The configured sessions value is the number of configured iSCSI sessions that will be created for each target name in a target portal group.

Select one of the following to modify the number of configured sessions either at the initiator node to apply to all targets or at a target level to apply to a specific target:
- Apply the desired parameter value to the iSCSI initiator node.
```
initiator# iscsiadm modify initiator-node -c 2
```
- Apply the desired parameter value to the iSCSI target.
```
initiator# iscsiadm modify target-param -c 2  iqn.1992-08.com.abcstorage:sn.84186266
```
- Bind configured sessions to one or more local IP addresses.
  Configured sessions can also be bound to a local IP address. Using this method, one or more local IP addresses are supplied in a comma-separated list. Each IP address represents an iSCSI session. This method can also be used at the initiator-node or target-param level. For example:
```
initiator# iscsiadm modify initiator-node -c 10.0.0.1,10.0.0.2
```
  Note - If the specified IP address is not routable, the address is ignored and the default Oracle Solaris route and IP address are used for this session.

Verify that the parameter was modified.

Display the updated information for the initiator node.

initiator# iscsiadm list initiator-node
Initiator node name: iqn.1986-03.com.sun:01:0003ba4d233b.425c293c
Initiator node alias: zzr1200
        .
        .
        .
        Configured Sessions: 2

Display the updated information for the target node.

initiator# iscsiadm list target-param -v iqn.1992-08.com.abcstorage:sn.84186266
Target: iqn.1992-08.com.abcstorage:sn.84186266
        Alias: -
        .
        .
        .
        Configured Sessions: 2

List the multiple paths to confirm that the OS device name matches the iscsiadm list output, and that the path count is 2 or more.
```
initiator# mpathadm list lu
```