| Document revision date: 30 March 2001 | |
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A major benefit of OpenVMS is its support of a wide range of interconnects and protocols for network configurations and for OpenVMS Cluster System configurations. This chapter describes OpenVMS Alpha support for Fibre Channel as a storage interconnect for single systems and as a shared storage interconnect for multihost OpenVMS Cluster systems.
The following topics are discussed:
For information about multipath support for Fibre Channel configurations, see <REFERENCE>(mult_sup_ch).
The Fibre Channel interconnect is shown generically in the figures in this chapter. It is represented as a horizontal line to which the node and storage subsystems are connected. Physically, the Fibre Channel interconnect is always radially wired from a switch, as shown in Figure 1-1. The representation of multiple SCSI disks and SCSI buses in a storage subsystem is also simplified. The multiple disks and SCSI buses, which one or more HSGx controllers serve as a logical unit to a host, are shown in the figures as a single logical unit. For ease of reference, the term HSG is used throughout this chapter to represent both an HSG60 and an HSG80, except where it is important to note any difference, as in Table 1-2. In those instances, HSG60 or HSG80 is used. |
Fibre Channel is an ANSI standard network and storage interconnect that offers many advantages over other interconnects. Its most important features are described in Table 1-1.
| Feature | Description |
|---|---|
| High-speed transmission | 1.06 gigabits per second, full duplex, serial interconnect (can simultaneously transmit and receive 100 megabytes of data per second) |
| Choice of media | OpenVMS support for fiber-optic media. Possible future support for copper media. |
| Long interconnect distances | OpenVMS support for multimode fiber at 500 meters per link and for single-mode fiber up to 100 kilometers per link. Possbile future support for 30-meter copper links. |
| Multiple protocols | OpenVMS support for SCSI--3. Possible future support for IP, 802.3, HIPPI, ATM, IPI, and others. |
| Numerous topologies | OpenVMS support for switched FC (highly scalable, multiple concurrent communications) and for multiple switches. Possible future support for mixed arbitrated loop and switches. |
Currently, the OpenVMS implementation supports:
Figure 1-1 shows a logical view of a switched topology. The FC nodes are either Alpha hosts, or storage subsystems. Each link from a node to the switch is a dedicated FC connection. The switch provides store-and-forward packet delivery between pairs of nodes. Concurrent communication between disjoint pairs of nodes is supported by the switch.
Figure 1-1 Switched Topology, Logical View
Figure 1-2 shows a physical view of a Fibre Channel switched topology. The configuration in Figure 1-2 is simplified for clarity. Typical configurations will have multiple Fibre Channel interconnects for high availability, as shown in Section 1.3.4.
Figure 1-2 Switched Topology, Physical View
OpenVMS Alpha supports the Fibre Channel devices listed in Table 1-2. Note that Fibre Channel hardware names typically use the letter G to designate hardware that is specific to Fibre Channel. Fibre Channel configurations with other Fibre Channel equipment are not supported. To determine the required minimum versions of the operating system and firmware, see the release notes.
Compaq recommends that all OpenVMS Fibre Channel
configurations use the latest update kit for the version of OpenVMS
that they are running:
The root name of these kits is FIBRE_SCSI, a change from the earlier
naming convention of FIBRECHAN. They are available from the following
web site:
OpenVMS supports the Fibre Channel SAN configurations described in the
latest StorageWorks Heterogeneous Storage Area Networks Application
Note, and the Data Replication Manager (DRM) user documentation. This
includes support for:
The StorageWorks documentation is available from their web site. First
locate the product; then you can access the documentation. The WWW
address is:
Within the configurations described in the StorageWorks documentation,
OpenVMS provides the following capabilities and restrictions:
This configuration support is in effect as of the revision date of this
document. OpenVMS plans to increase these limits in future releases.
In addition to the configurations already described,
OpenVMS also supports the SANworks Data Replication Manager. This is a
remote data vaulting solution that enables the use of Fibre Channel
over longer distances. For more information, see the Compaq
StorageWorks web site at:
Qualification of new Fibre Channel hardware and larger configurations
is ongoing. New hardware and larger configurations may necessitate
enhancements to the Fibre Channel support in OpenVMS. Between releases
of OpenVMS, enhancements and corrections to Fibre Channel software are
made available by means of remedial kits. Compaq recommends that you
monitor the Fibre Channel web site (
http://www.openvms.compaq.com/openvms/fibre/
) and the Compaq support web site (
http://www.compaq.com/support/
) for updates for the operating system version you are running.
The latest version of each kit is always posted to the Compaq support
web site.
Shared Fibre Channel OpenVMS Cluster storage is supported in both
mixed-version and mixed-architecture OpenVMS Cluster systems. The
following configuration requirements must be observed:
Since Fibre Channel support was introduced in OpenVMS Alpha, shadowing
of directly connected Fibre Channel storage using Volume Shadowing for
OpenVMS, has been available. OpenVMS Alpha Version 7.2-1 extended this
support to the shadowing of Fibre Channel multipath devices.
Note to developers: Can following be removed?
Currently, a limitation exists in shadowing support on multiple-switch
fabrics (also known as cascaded switches). When Volume Shadowing for
OpenVMS is used, all the Fibre Channel hosts that mount the shadow set
members must be connected to the same switch, or all the Fibre Channel
shadow set members must be connected to the same switch. If the Fibre
Channel host or shadow set member is connected to multiple-switch
fabrics, then this rule must be followed for each fabric. This
limitation is expected to be removed soon.
Fibre Channel is supported in all OpenVMS Galaxy configurations. For
more information about Galaxy configurations, see the OpenVMS Alpha Partitioning and Galaxy Guide.
This section presents example Fibre Channel configurations. The
configurations build on each other, starting with the smallest valid
configuration and adding redundant components for increasing levels of
availability, performance, and scalability.
Figure 1-3 shows a single system using Fibre Channel as a storage
interconnect.
Figure 1-3 Single Host With One Dual-Ported Storage
Controller
Note the following about this configuration:
Figure 1-4 shows multiple hosts connected to a dual-ported storage
subsystem.
Figure 1-4 Multiple Hosts With One Dual-Ported Storage
Controller
Note the following about this configuration:
Figure 1-5 Multiple Hosts With Storage Controller
Redundancy
This configuration offers the following advantages:
Figure 1-6 Multiple Hosts With Multiple Independent
Switches
This two-switch configuration offers the advantages of the previous
configurations plus the following:
Figure 1-7 Multiple Hosts With Dual Fabrics
This dual-fabric configuration offers the advantages of the previous
configurations plus the following advantages:
Figure 1-8 shows multiple hosts connected to two fabrics. Each fabric
has four switches.
Figure 1-8 Multiple Hosts With Larger Dual Fabrics
Figure 1-9 shows multiple hosts connected to four fabrics. Each
fabric has four switches.
Figure 1-9 Multiple Hosts With Four Fabrics
Fibre Channel devices for disk and tape storage come
with factory-assigned worldwide IDs (WWIDs). These WWIDs are used by
the system for automatic FC address assignment. The FC WWIDs
and addresses also provide the means for the system manager to identify
and locate devices in the FC configuration. The FC WWIDs and adresses
are displayed, for example, by the Alpha console and by the HSG
console. It is necessary, therefore, for the system manager to
understand the meaning of these identifiers and how they relate to
OpenVMS device names.
In most situations, Fibre Channel devices are configured to have
temporary addresses. The device's address is assigned automatically
each time the interconnect initializes. The device may receive a new
address each time a Fibre Channel is reconfigured and reinitialized.
This is done so that Fibre Channel devices do not require the use of
address jumpers. There is one Fibre Channel address per port, as shown
in Figure 1-10.
Figure 1-10 Fibre Channel Host and Port Addresses
In order to provide more permanent identification, each port on each
device has a WWID, which is assigned at the factory. Every Fibre
Channel WWID is unique. Fibre Channel also has node WWIDs to identify
multiported devices. WWIDs are used by the system to detect and recover
from automatic address changes. They are useful to system managers for
identifying and locating physical devices.
Figure 1-11 shows Fibre Channel components with their factory-assigned
WWIDs and their Fibre Channel addresses.
Figure 1-11 Fibre Channel Host and Port WWIDs and
Addresses
Note the following about this figure:
http://www.compaq.com/support/
Component Name
Description
AlphaServer 800,
1
1000A,
2
1200, 4000, 4100,
8200, 8400, DS10, DS20, DS20E, ES40, GS60, GS60E, GS80,
GS140, GS160, and GS320
Alpha
host.
HSG80
Fibre Channel controller module with two Fibre Channel host ports and
support for six SCSI drive buses. One or two HSG80s can be used in a
Fibre Channel RAID storage cabinet.
HSG60
Fibre Channel controller module with two Fibre Channel host ports and
support for two SCSI buses. One or two HSG60s can be used in a Fibre
Channel RAID storage cabinet.
MDR
Fibre Channel Modular Data Router,
a switch to a SCSI tape library. The MDR must be
connected to a Fibre
Channel switch. It cannot be connected directly to an
Alpha system.
KGPSA-BC, KGPSA-CA
OpenVMS Alpha PCI to multimode Fibre Channel host adapters.
DSGGA-AA or -AB and DSGGB-AA or -AB
8-port or 16-port Fibre Channel switch.
BNGBX-
nn
Multimode fiber-optic cable (
nn denotes length in meters).
1On the AlphaServer 800, the integral S3 Trio must be
disabled when the KGPSA is installed.
2Console support for FC disks is not available on this model.
www.compaq.com/storage
If your FC
fabric is large, and the number of active connections exceeds the HSG
limit, then you must reconfigure the fabric, or use FC switch zoning to
"hide" some of the adapters from some of the HSG ports, in order to
reduce the number of connections.
The HSG does not delete
connection information from the connection table when a host bus
adapter is disconnected. Instead, the user must prevent the table from
becoming full by explicitly deleting the connection information using a
CLI command.
http://www.compaq.com/products/storageworks
1.2.1 Fibre Channel Remedial Kits
1.2.2 Mixed-Version and Mixed-Architecture Cluster Support
7.3
7.2-1H1
7.2-1
7.2 with the DEC-AXPVMS-VMS72_HARDWARE-V0100--4.PCSI remedial kit
and console revision 5.4 or higher, depending on the AlphaServer model
(see the release notes)
1.2.3 Fibre Channel and Volume Shadowing for OpenVMS
1.2.4 Fibre Channel and OpenVMS Galaxy Configurations
1.3 Example Configurations
1.3.1 Single Host with Dual-Ported Storage
1.3.2 Multiple Hosts With One Dual-Ported Storage Controller
1.3.3 Multiple Hosts With Storage Controller Redundancy
Figure 1-5 shows multiple hosts connected to two dual-ported storage
controllers.
1.3.4 Multiple Hosts With Multiple Independent Switches
Figure 1-6 shows multiple hosts connected to two switches, each of
which is connected to a pair of dual-ported storage controllers.
1.3.5 Multiple Hosts With Dual Fabrics
Figure 1-7 shows multiple hosts connected to two fabrics; each fabric
consists of two switches.
1.3.6 Multiple Hosts With Larger Fabrics
The configurations shown in this section offer even higher levels of
performance and scalability.
1.4 Fibre Channel Addresses, WWIDs, and Device Names
1.4.1 Fibre Channel Addresses and WWIDs
(This is true in the current implementation.)
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