HP Fibre Channel Fabric Migration Guide Edition 5 HP Fibre Channel Mass Storage Manufacturing Part Number: J2635-90014 E1201 United States © Copyright 2000, 2001 Hewlett-Packard Company.
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Contents . Fabric Migration Guide Migrating to Fabric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Important Considerations of Migrating to Fabric. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Device File Addressing Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Requirements for Arbitrated Loop and Fabric Support . . . . . . . . . . . . . . . . . . . . . . . .
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Fabric Migration Guide This document describes the fabric feature for the Fibre Channel PCI Tachyon TL, HSC TL and PCI XL2 host bus adapters. It lists the requirements you will need to take advantage of this feature along with any restrictions in using fabric.
Fabric Migration Guide Migrating to Fabric Migrating to Fabric A Fibre Channel fabric (one or more switches in a configuration) can provide multiple benefits including independent bandwidth per port, greater reliability, and increased performance. Before you change your environment to a fabric supported environment, read the following sections carefully.
Fabric Migration Guide Migrating to Fabric the I/O is timed out and then retried for direct access devices. It can also cause a loss of position for sequential access devices, and the entire operation may need to be retried. • Simpler link level protocol results in fewer chances of encountering hardware, firmware, or software defects in the HBAs. • A fabric environment can provide multiple paths of communication between initiator and the target on the loop.
Fabric Migration Guide Migrating to Fabric Scalability • Fabrics allow you to expand beyond a single loop with a maximum of 126 loop ports to a SAN environment where it is possible to use multiple fabrics and attach virtually unlimited numbers of devices in several configurations. • In addition to attaching devices directly to the fabric or having public loops in the SAN, you can attach an existing (but separate) private loop to the fabric, and have all of the devices managed by the fabric.
Fabric Migration Guide Migrating to Fabric — A5158A HP-UX 11.00 or 11i software driver. The driver is available on the web at http://www.software.hp.com and on the HP-UX Application CD, AR0301 and later. The 11i driver is always installed with the HP-UX 11i Operating Environment. — Tachyon patch PHKL_23939 or later for HP-UX 11.00 — Tachyon patch PHKL_23626 or later for HP-UX 11i • A6684A and A6685A HSC Tachlite adapters — OS version HP-UX 10.20, 11.00 or 11i — A6684A/A6685A 10.20, 11.
Fabric Migration Guide Migrating to Fabric Restrictions • All target loop devices are required to continue using hard physical addressing. • Remote device or LUN level scanning from IODC is not supported. • fcmsutil option, echo, cannot be used in a fabric configuration. • The maximum number of Tachyon TL hosts that HP recommends on an FL_Port is nine in non-HA configurations and four in HA configurations.
Fabric Migration Guide Supported Fabric Configurations Supported Fabric Configurations HP currently supports the following SAN configurations with the A5158A PCI Tachyon TL adapter, the A6684A and A6685A HSC Tachlite adapters and the A6795A PCI 2Gb XL2 adapter.
Fabric Migration Guide Supported Fabric Configurations This isolated private loop is a typical configuration. It uses two hubs for some redundancy to the target devices. This configuration will continue to be supported. Direct Fabric Attachment A simple migration to a fabric configuration is to replace the two hubs with two Fibre Channel switches. Redundant paths to the targets are maintained while each link is isolated from each other providing better performance and reliability.
Fabric Migration Guide Supported Fabric Configurations QuickLoop Attachment for Fabric A migration path to a fabric configuration with devices that are not fabric capable is to use the QuickLoop fabric configuration. In this configuration, a host connected to a F_Port or FL_Port on the switch can communicate with private target devices connected to QL ports in the same or different loop.
Fabric Migration Guide Supported Fabric Configurations QuickLoop Attachment for Private Devices NOTE The following configuration can be used when you are in the process of migrating to fabric but your fabric environment is not yet fully functional. In a private loop environment, a QuickLoop configuration can allow private hosts with a Tachyon adapter attached to a QL_Port to access private devices on the loop by using the switch as a hub.
Fabric Migration Guide Supported Fabric Configurations Public Loop A public loop is an arbitrated loop where at least one of the ports on the loop is a switch port (FL_Port), which allows hosts or devices on the loop to communicate with hosts or devices attached to other FL_Ports. Figure 0-5 shows that Host 1 and Host 2 are public hosts connected through a hub to an FL_Port on the switch. The target devices are public devices (NL_Ports) connected to other FL_Ports.
Fabric Migration Guide Fabric Device Addressing Changes Fabric Device Addressing Changes When you migrate from an existing Fibre Channel private loop configuration to a switched Fibre Channel fabric configuration, the hardware path to the attached target devices will change to reflect the presence of a fabric/switch in the route from the host initiator to the target device. When the I/O path information to a given disk changes, a new device file is created for this device.
Fabric Migration Guide Fabric Device Addressing Changes Device Addressing in a Fabric Environment HP’s current model of addressing associates devices with their hardware path information. In the case of Fibre Channel disk devices, the device file names are little more than tags that are associated with a node in the system iotree. Using the ioscan command, ioscan -kfn -C disk, you can obtain this association.
Fabric Migration Guide Fabric Device Addressing Changes Figure 0-6 Annex-K - Assigned Loop Identifier Note that the values are from lowest to highest priority. AL_PA=00 is reserved for an FL_Port; “-” is not available. Because HP continues to use Physical Path addressing, loop devices (public and private) will be required to continue using Hard Physical Addresses.
Fabric Migration Guide Fabric Device Addressing Changes Private Loop to Fabric Example Following is a simple example of migrating an HP disk device from a private loop configuration to a fabric topology. Figure 0-7 shows a private loop configuration.
Fabric Migration Guide Fabric Device Addressing Changes Figure 0-8 shows a Direct Fabric Attachment configuration. Figure 0-8 Direct Fabric Attachment Configuration Host Switch Disk Device The ioscan output for this configuration could be as follows: Class I H/W Path Driver S/W State H/W Type Description ----------------------------------------------------------------------------fc 0 0/1/2/0 td CLAIMED INTERFACE HP Tachyon TL/TS Fibre Channel Mass Storage Adapter fcp 1 0/1/2/0.
Fabric Migration Guide Fabric Device Addressing Changes CAUTION Do not configure switches with a domain of 8. This configuration is unsupported and will not work. HP systems reserve domain 8 for Private Loop devices. • The fabric configuration now contains an iotree node of 0/1/2/0.1 described as FCP Domain. A node of this type will be built for each domain the fabric contains. (Domains generally correspond one to one with a physical instance of a switch).
Fabric Migration Guide Fabric Device Addressing Changes • All targets and disk devices retain their original iotree addresses except for the new fabric N_Port address which is substituted for the old Arbitrated Loop address. • New device files will be generated for the new iotree nodes. The old device files will continue to exist until they are removed with the rmsf command or a system reboot.
Glossary A AL Boot - the process of booting from a device that is on the same arbitrated loop as the host adapter. No switch is required. Arbitrated Loop - a Fibre Channel topology where information is routed around the loop from port to port until it arrives at its destination. This is a private loop configuration. Area - the second field of the 3-byte address assigned to an attached N_Port in a Fabric configuration. The Area is generally associated with an F/FL port on a switch.
FC-AL - (Fibre Channel Arbitrated Loop) - the ANSI standard that describes how several Fibre Channel ports can share a single communication ring. F_Port (Fabric Port) - a port within the Fabric used to route frames from N_Port to N_Port. The F_Port is the access point to a Fibre Channel switch. FC-SW (Fibre Channel Switch Fabric) - the standard that describes how Fibre Channel switches are required to behave.
The port is generally associated with the Hard Physical Address (HPA) of a Fibre Channel target device. multiple private Arbitrated Loops that are interconnected and may be isolated by the switch (this is a feature of the Brocade switches). Private Loop - an arbitrated loop that has no attached switch port. Private loop devices can only communicate with other devices on the same loop (except in translative mode). See also Translative Mode and Arbitrated Loop.
