Spectra Logic T-Series Spectra T950 User Manual page 57

Chapter 5. Library Partitioning
Configuration Note: Using DHCP in iSNS Environments
Use of any of these options requires communication to an external server over the
network. If this server is unavailable or cannot be reached when the library powers up,
the QIP may be unusable and may need to be reset after the server becomes ready.
Using DHCP.
DHCP provides all the Ethernet setup information necessary to
communicate on a network. An external DHCP server on the network provides the
Ethernet setup information to the library. If the DHCP server is not present or cannot
be reached when the library powers up, the library will not be able to communicate
with any host on the network. On power up, when DHCP is enabled, the library
searches for a DHCP server indefinitely. If a DHCP server does not respond within
three minutes, a warning message is sent to the LC. The QIP may need to be reset to
re-initiate the DHCP server scan.
During the creation of a partition, you are asked to enter a host name for the ports on
the E-QIP. This hostname is not registered with the DHCP server. Therefore, the only
way to address the iSCSI port on the QIP is by IP address. If you are using DHCP, you
must get the DHCP-assigned IP address directly from the DHCP server.
An alternative to knowing the DHCP IP address of the QIP is to enable and configure
iSNS for the DHCP port. The iSNS server can discover and identify the QIP. The iSNS
server tracks the DHCP IP address and iSCSI name, and reports that information to any
iSNS-aware iSCSI initiator.
Using iSNS.
The iSCSI Storage Name Service (iSNS) server maintains a list of iSCSI
target names and associated IP addresses for the iSCSI devices on the network. When
iSNS is enabled, the QIP registers its iSCSI name and IP address with the iSNS server.
The list of iSCSI devices on the network is made available to initiators for use in
establishing a connection without knowing the host name or IP address of the iSCSI
device.
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