Establishing Initiator/Target Connections for iSCSI

Instructions are provided In this guide to configure iSCSI initiators and targets on storage servers. In order to mirror over iSCSI, storage servers must have the iSCSI initiator configured (following the instructions below) because storage servers will act as both initiator and target.

CAUTION:  By default, no more than 16 iSCSI initiator connections are allowed to an iSCSI target at any one time.
For example, if you have more than 8 application servers, each with 2 iSCSI connections each, only the first 8 application servers will be able to connect to the storage server iSCSI target. All other connections will be refused.

CAUTION:  If the Microsoft iSCSI Initiator software in Windows is upgraded on the storage server, you must manually run the DcsInstallTasks.exe, an executable that sets important default values for iSCSI communications. This executable file is available from a FAQ on the Technical Support Web site.

Before you begin, ensure you have completed the steps pertaining to iSCSI as outlined in the Pre-installation Steps:   

• If applicable, iSCSI Initiator software should be installed on all storage and application servers.

• Microsoft iSCSI Initiator Service should be started on all storage servers if you intend to mirror over iSCSI.
   (The service can be started from Server Manager>Configuration>Services. When you start the service, you will receive a message to unblock the service so it can communicate through the Windows Firewall. Click Yes on the message.
  WARNING:  In Microsoft iSCSI Initiator, do not enable the Microsoft MPIO Multipathing Support for iSCSI option— even if you will be using  MPIO.

• If you are using an iSNS server, the server should be accessible over the network and have iSNS software installed.

For more information, review:

• Best Practices for iSCSI High Availability

• iSCSI Security and Error Detection

• About Alternate Pathing and MPIO

 

Perform the following steps to establish connections for initiators and targets:

1. Ensure your channels have meaningful aliases to facilitate channel discovery and establish connections:

   • Customize the default target channel aliases in SANmanager. Refer to Changing Channel Aliases for instructions.

   • If applicable, customize the default initiator channel alias in the iSCSI Manager tool in SANsymphony Console. Refer to iSCSI Initiator Properties in iSCSI Manager for instructions.

2. All iSCSI initiators must discover the target portals in your configuration:

   • Configure the application servers to discover the storage server targets using the instructions for your specific operating system and iSCSI initiator software.

   • If you are mirroring over iSCSI, configure the storage servers as initiators. Initiators can be configured using iSNS or manual discovery. Select the appropriate topic:

   • • Automatic Discovery of iSCSI Initiator/Targets using iSNS.

     • Add or Remove iSCSI Targets Using iSCSI Manager

3. From the configured initiators, log on to iSCSI targets in order to access the target storage devices.

• • On application servers,  log on to targets using the instructions for your specific operating system and iSCSI initiator software.

  • On storage servers acting as initiators, use the iSCSI Manager tool in SANsymphony Console, refer to Logging on to Targets Using the iSCSI Manager tool.

 

For more iSCSI menu items, refer to iSCSI Manager.

 

Establishing Initiator/Target Connections for iSCSI