Oracle FS Path Manager (FSPM) for AIX supports Internet Small Computer System Interface (iSCSI) connections. The following information will help you configure iSCSI to work with FSPM and your Oracle FS System.
The unit of configuration for iSCSI on AIX is a logical device called an iSCSI protocol device. One iSCSI protocol device represents the iSCSI software initiator, which operates over the normal Transmission Control Protocol (TCP) / Internet Protocol (IP) stack and the network interface cards (NICs) that TCP/IP is configured to use. Each iSCSI TCP Offload Engine (TOE) or host bus adapter (HBA) port also has its own iSCSI protocol device.
Each iSCSI protocol device can connect to a maximum of one port on each iSCSI target. An
Oracle FS System is a single iSCSI target with multiple iSCSI ports. This means that each iSCSI protocol device can connect to only one
Controller port on an
Oracle FS System. To make multipath connections to a
Oracle FS System LUN, the host must have a minimum of two iSCSI protocol devices. For example, these protocol devices could be one of:
- The software initiator and one HBA
- Two HBAs
This enables two connections to the
Oracle FS System, which would be enough to enable minimal multipathing for a dual-
Controller Oracle FS System.
To enable multipathing, the target discovery policy for each iSCSI protocol device must be configured to ensure that they discover the appropriate Controller ports. For example, with two iSCSI protocol devices, one should be configured to only discover a port on one Controller, and the other should be configured to discover a port on the other Controller.
There are several ways to configure target discovery (or explicitly configure target ports) for each iSCSI protocol device, a few of which are documented in the AIX documentation. The ability of
FSPM to automatically discover the management IP addresses of attached
Oracle FS System varies with how target discovery is configured.
- If an iSCSI protocol device is configured to use the file or Object Data Manager (ODM) discovery policies, FSPM will be able to discover Oracle FS System Pilots without additional configuration. As long as it is possible to make an iSCSI connection between the relevant host and Controller ports, FSPM will automatically find the Pilot IP address.
- For discovery policies other than file or ODM, the iSCSI protocol device must first bring an iSCSI LUN on the Oracle FS System online. This involves typing in the initiator name of the iSCSI protocol device at the Oracle FS System and mapping a LUN to it, or making a LUN globally visible over iSCSI from the Oracle FS System, and then running the cfgmgr command on the host.
FSPM will be able to discover the
Oracle FS System management address, even if the
LUN itself is deleted or unmapped at the
Oracle FS System, as long as the following conditions are true:
- The configuration information exists on the host for an iSCSI LUN on the Oracle FS System.
- It is possible to make an iSCSI connection between the relevant host and Controller ports.
Important! AIX does not support the configuration of combo LUNs.
Combo LUNs are LUNs that are accessible through both Fibre Channel and iSCSI. A LUN on an Oracle FS System must not be made visible to AIX over Fibre Channel and iSCSI at the same time or the LUN configuration at the host will become confused and behave unpredictably.
If a LUN has been accessible by the host in the past over one protocol, and the same LUN is to be made accessible over the other protocol, then the LUN’s existing configuration information should be deleted from AIX before making it accessible over the new protocol. The configuration information is deleted by using the rmdev command:
Example:
rmdev -l hdiskx -d
Where
hdiskx is the name and number of an hdisk device.