IBM N Series, Hardware Manual

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Chapter 17. Host Utilities Kits
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򐂰 For iSCSI connections, create an iSCSI igroup that uses the iSCSI node name of the host.
򐂰 For systems that use both FC and iSCSI connections to the same LUN, create two
igroups: One for FC and one for iSCSI. Then, map the LUN to both igroups.
There are many ways to create and manage initiator groups and LUNs on your storage
system. These processes vary depending on your configuration.
Mapping LUNs to igroups
When you map a LUN to an igroup, assign the LUN identifier. You must assign the LUN ID of
0 to any LUN that is used as a boot device. LUNs with IDs other than 0 are not supported as
boot devices.
If you map a LUN to both a Fibre Channel igroup and an iSCSI igroup, the LUN has two
different LUN identifiers.
17.5.3 Mapping LUNs for Windows clusters
When you use clustered Windows systems, all members of the cluster must access LUNs for
shared disks. Map shared LUNs to an igroup for each node in the cluster.
17.5.4 Adding iSCSI targets
To access LUNs when you are using iSCSI, you must add an entry for the storage system by
using the Microsoft iSCSI Initiator GUI. To add a target, complete the following steps:
1. Run the Microsoft iSCSI Initiator GUI.
2. On the Discovery tab, create an entry for the storage system.
3. On the Targets tab, log on to the storage system.
4. If you want the LUNs to be persistent across host reboots, select Automatically restore
this connection when the system boots when you are logging on to the target.
5. If you are using MPIO or multiple connections per session, create more connections to the
target as needed.
Enabling the optional MPIO support or multiple-connections-per-session support does not
automatically create multiple connections between the host and storage system. You must
explicitly create the other connections.
Restriction: The Windows operating system recognizes only LUNs with identifiers 0 - 254,
regardless of the number of LUNs mapped. Be sure to map your LUNs to numbers in this
range.
Requirement: If more than one host is mapped to a LUN, you must run clustering software
on the hosts to prevent data corruption.