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Configuring RAC logical disks AIX

There are two FC protocols, depending on whether an FC switch (fabric configuration) or an FC HUB (arbitrated loop) is used:


The nodes are connected directly to the ESS, excluding any network equipment. Choose Arbitrated Loop (al protocol). This is the default value.

The nodes are connected to a SAN, using a switch. Select Point-to-Point (pt2pt protocol).

Because our platform is using a switched SAN, the point-to-point protocol is selected on all nodes and ESS Fibre Channel adapters.

To view the actual value set on the FC adapter:

{node3:root}/-> lsattr -El fcs0
grep init_linkinit_link al INIT Link flags TrueTo change this value, use "smitty devices", select the FC Adapter menu, and change the field INIT Link flags. Or, you can use the command:

{node3:root}/-> chdev -l fcs0 -a init_link=pt2pt

If you are unsure about the way your nodes are connected to the disk subsystems, choose init_link=al. This setting first tries to detect a switch. If that fails, it changes to arbitrated loop. It is like an auto detect feature. The FC adapter will recognize the device it is connected to, that is, FC hub or switch.

Check whether all fiber cables are connected (nodes to FC switch, FC switch to ESS). This step assumes that the ESS storage configuration has been performed and checked.

For consistency, we recommend that you remove any previous definition of the FC adapters and their child devices, then run a fresh cfgmgr. On each node and for each FC adapter, issue:

{node3:root}/-> rmdev -Rdl fcs0

{node3:root}/-> cfgmgr

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