iSCSI Communication Between the Storage Array and Host Server
All MD-series iSCSI storage arrays have either two or four iSCSI host ports per RAID controller module
(see Figures 4 and 5). These host ports are used to establish iSCSI sessions between the storage array
and host server. To be able to write data to the storage array, the host server must be able to establish
a successful iSCSI session with at least one port per RAID controller module.
How are iSCSI Sessions Established?
A basic overview of how an iSCSI session is set up between the iSCSI host ports on your storage array
and the host server is below:
Step 1: The iSCSI initiator on the host server sends a discovery session command to the storage
array.
Step 2: The MD storage array responds with a list of available iSCSI host ports.
Step 3: Depending on how the iSCSI initiator is configured (the iSCSI initiator can be configured to
connect to all storage array ports or a specific set of ports), the host server attempts to log in to
available iSCSI ports on the storage array.
Step 4: A successful log in by the host server to a storage array port establishes an iSCSI session.
Enabling IPv4 or IPv6
IPv4 and IPv6 are both supported protocols on the MD-series iSCSI storage arrays. Whichever one you
use, be aware of the following with either protocol:
It is possible to enable both IPv6 and IPv4 on your host server. However, Dell recommends that
you disable the one you are not using before setting up your storage array. Having both
enabled may cause miscommunication between the storage array and host server.
Make sure that the protocol you choose is enabled on both the storage array and host server.
Mixing protocols (for example, enabling IPv4 on the storage array and IPv6 on the host server)
will cause session interrupts and possible loss of data.
Should I Set Up iSCSI Sessions Automatically or Manually?
NOTE:
In most cases, Dell recommends that you set up iSCSI communication between your host
server and storage array automatically using the Dell MD Configuration Utility (MDCU)
supplied on the installation DVD. However, since this document focuses mostly on
troubleshooting problems that occur during iSCSI host port setup, the process of setting up
iSCSI manually using MD Storage Manager is emphasized. For information on using MDCU, see
the Help link in the utility itself.
Setting Up iSCSI Automatically: Using the Dell MD Configuration Utility
Using the Dell MD Configuration Utility is the easiest way to set up iSCSI communication between your
storage array and host server.
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