HP OpenVMS Systems Documentation

Guidelines for OpenVMS Cluster Configurations

7.5.2.3 File-Based Device Naming

Fibre Channel tape and medium changer devices are configured according to information found in the SYS$SYSTEM:SYS$DEVICES.DAT file. This is an ASCII file consisting of two consecutive records per device, where the two records are in the following form:

[Device $2$devnam] 
WWID = displayable_identifier

During autoconfiguration, the Fibre Channel is probed and the WWIDs are fetched for all devices. If the fetched WWID matches an entry in the memory-resident copy of the SYS$DEVICES.DAT file, then the device is configured using the device name that has been paired with that WWID.

Note

The SYS$DEVICES.DAT file is also used for port allocation class (PAC) information. Fibre Channel tape-naming is a second use of this same file, even though PACs and Fibre Channel tapes are not related, other than their common need to access file-based device information at boot time.

By default, the SYS$DEVICES.DAT file is created in the cluster common directory, SYS$COMMON:[SYSEXE].

As an example, the following portion of SYS$DEVICES.DAT causes the eventual configuration of devices named $2$MGA300 and $2$MGA23:

! 
[Device $2$MGA300] 
WWID = 04100022:"COMPAQ  DLT8000         JF71209240"   
! 
[Device $2$mga23] 
WWID = 04100022:"DEC     TZ89     (C) DECJL01164302"

Although the file is typically read and written only by OpenVMS utilities, in rare instances you may need to edit the file. You can change only the unit number of the device, as described in Section 7.5.5. The internal syntax rules governing the file are summarized as follows:

Comment lines (beginning with !) and blank lines are permitted.
Any white space (or none) can separate [Device from the device name represented by $2$xxx ].
Failure to supply the $2$ prefix will result in a console warning.

Similarly, on the line containing WWID = , any white space (or none) can appear on either side of the equals sign. All lines must be left-justified, and all lines must be less than 512 characters.

The parsing of this file is not case sensitive, with one important exception: all characters enclosed within double quotation marks are taken literally, so that characters such as spaces and lowercase letters are significant. In the case of ASCII data enclosed by double quotation marks, there must be no space between the colon and the double quotation mark.

Also, if more than one WWID = line follows a single [Device devnam] line, the last WWID = value takes precedence. Normally, however, there is exactly one WWID = line per [Device devnam] line.

Similarly, if two or more [Device devnam] lines specify the same device name but different WWIDs, only the last device name and WWID specified in the file is used.

This file is read at boot time, and it is also read from and written to by the SYSMAN IO FIND_WWID command. If there are additional system-specific copies of the SYS$DEVICES.DAT file, their tape naming records become automatically compatible as a result of running SYSMAN IO FIND_WWID on each system. The SYSMAN IO FIND_WWID command is described in more detail in the following section. The SYS$DEVICES.DAT file may also be modified by the SYSMAN IO CREATE_WWID and REPLACE_WWID commands which are described below.

7.5.3 Management Support for Fibre Channel Tape Devices

The following System Management utility (SYSMAN) commands are provided for managing Fibre Channel tape devices:

IO FIND_WWID
Probes all ports on the Fibre Channel and detects all previously undiscovered tapes and medium changers, and assigns a name to each. Displays a list of the devices and their assigned device names, and automatically records this information in the SYS$SYSTEM:SYS$DEVICES.DAT file. Also updates relevant local and clusterwide memory structures. It should be executed clusterwide.
Use this command prior to running the SYSMAN command IO AUTOCONFIGURE.
Requires the CMKRNL privilege.
IO LIST_WWID
Lists all tape device WWIDs that are not yet configured on Fibre Channel. Use this command prior to running the SYSMAN command IO CREATE_WWID.
Requires the CMKRNL privilege.
IO CREATE_WWID
Enables the user to assign a specific (and previously unused) device name to a specific (and previously unused) WWID from the SYSMAN IO LIST_WWID display. It should be executed clusterwide. The command should then be followed by a clusterwide SYSMAN IO AUTO command to actually configure the device.
This command offers an alternative to the SYSMAN IO FIND_WWID command, which chooses system-generated device names for the discovered WWIDs. The IO CREATE command should not be used after the IO FIND command as a means of redefining WWID correlations. The device and WWID strings specified in IO CREATE_WWID should not be in use elsewhere in the cluster.
Requires the CMKRNL privilege.
IO REPLACE_WWID
Updates appropriate file and memory data structures in case one tape drive must be physically replaced by another tape drive at the same FC LUN location.
Requires the CMKRNL privilege.

The following DCL support for Fibre Channel tape devices is available:

The SHOW DEVICE/FULL command displays the WWID for Fibre Channel tape devices.
The F$GETDVI lexical function supports the keyword WWID , which returns the Fibre Channel tape device's WWID.

7.5.4 Configuring a Fibre Channel Tape Device

This section lists the steps required to configure a new tape or medium changer on the Fibre Channel.

7.5.4.1 Basic Configuration Steps: Summary

The basic steps for configuring new Fibre Channel tape devices in a cluster are as follows:

Power on the new tape device or devices.
If you are using the MDR, power cycle the MDR to update MDR mapping information.
If you are using the NSR, use Visual Manager to update the mapping information as follows:
- Click on the Mapping submenu. Username is root, password is password.
- Ensure the Select Map box indicates Indexed mode.
- Click on the Edit/View box that is next to the Select Map box.
- This brings up an empty indexed map. Under the Priority option, select Target/Bus Priority and then click on Fill Map. Note that the Target/Bus priority ensures that the controller LUN, also known as the Active Fabric (AF) LUN, is mapped to LUN 0.
- The new map appears. Close that window, which then returns you to the Mapping submenu.
- If the NSR has additional FC ports besides FC port 0, click on FC Port 1 and repeat the mapping process for FC Port 1, and any other FC ports.
- Click on Reboot to make the updates to the maps take effect.
  Further details on the Visual Manager are documented in the hp StorageWorks Network Storage Router M2402 user guide.

Run SYSMAN to assign device names and configure the devices:

$ MC SYSMAN 
SYSMAN> SET ENVIRONMENT/CLUSTER        ! Execute on all nodes 
SYSMAN> IO FIND_WWID                   ! Assign names 
SYSMAN> IO AUTOCONFIGURE/LOG           ! Configure devices 
SYSMAN> EXIT

You need to perform these steps only once for the initial configuration. After any subsequent system reboot, the devices will appear automatically.

7.5.4.2 Basic Configuration Steps: Details

Prior to configuring a tape device on Fibre Channel, the worldwide identifier (WWID) of the device must be detected and stored, along with a device name, in the text file SYS$SYSTEM:SYS$DEVICES.DAT. This is usually accomplished by using the SYSMAN command IO FIND_WWID. However, some users prefer to choose their own devices name for the tape devices, rather than using the system-generated names assigned by FIND_WWID. In that case, the user will execute the IO CREATE_WWID command instead of IO FIND_WWID. IO CREATE_WWID will be described in the next section, while this current section documents the use of IO FIND_WWID.

The IO FIND_WWID command probes all ports on the Fibre Channel and locates all tape and medium changer devices connected to an MDR or NSR. For tapes and medium changers that have not been detected by a previous IO FIND_WWID command, IO FIND_WWID assigns a device name, retrieves the WWID of the device, stores the device name and WWID data in the SYS$SYSTEM:SYS$DEVICES.DAT file, and updates memory structures.

Since the primary goal of IO FIND_WWID is to populate the SYS$DEVICES.DAT file, you need to invoke the IO FIND_WWID command only once for each device. IO FIND_WWID does not configure the $2$MGAnnnn: device for use by an application.

Once the information is stored in the file, subsequent use of the IO AUTOCONFIGURE command reads a memory-resident copy of the file and configures the tape and medium changer devices automatically, loading or connecting the device drivers as needed. The SYS$DEVICES.DAT file is read into memory during each system reboot; this action initiates the automatic configuration of tapes and medium changers on the Fibre Channel.

Note that running the IO FIND_WWID command for the first time detects all existing tape and medium changer devices on the system. If you add additional Fibre Channel tape devices to the system at a later time, you must first powercycle the MDR to update internal mapping information, and then run the IO FIND_WWID command again to append the new device information to the SYS$DEVICES.DAT file. On an NSR, edit the indexed map to update mapping information.

In an OpenVMS Cluster environment, various data structures in memory must be updated on each system when a new Fibre Channel tape device is added. To accomplish this, HP recommends that you run the SYSMAN IO FIND_WWID command on each Alpha node in the cluster. Alternatively, you can run IO FIND_WWID on one node, and then reboot the other nodes that share that same system disk, because the SYS$DEVICES.DAT file is read at boot time and causes memory structures to be correctly initialized.

In the case of multiple system disks in the cluster, ensure that all copies of the SYS$DEVICES.DAT file are kept consistent, preferably by running the IO FIND_WWID command on all nodes. Alternatively, you can run IO FIND_WWID to update just one SYS$DEVICES.DAT file, and then manually edit the remaining SYS$DEVICES.DAT files by cutting and pasting the appropriate device name and WWID records from the original file to the target files. If this second alternative is used, however, the remaining nodes must be rebooted in order for the memory-resident copy of SYS$DEVICES.DAT to be updated.

HP recommends that you refrain from copying the entire original file to another system disk. The SYS$DEVICES.DAT file is also used to define port allocation classes (PACs), and PAC entries could be transferred inadvertently to the target system.

Following is a configuration example using a TL891 tape library on a single node.

First, the SYSMAN command IO FIND_WWID displays a list of all previously undiscovered tape devices and their proposed device names.

$ MCR SYSMAN IO FIND_WWID 
 
%SYSMAN-I-OUTPUT, command execution on node SAMPLE 
On port _SAMPLE$PGA0:, the following tape WWIDs and their proposed device 
names have been found but not yet configured: 
 
      [Device $2$GGA0] 
      WWID=04100024:"DEC     TL800    (C) DEC3G9CCR82A017" 
 
      [Device $2$MGA0] 
      WWID=04100022:"DEC     TZ89     (C) DECCX939S2777" 
 
      [Device $2$MGA1] 
      WWID=04100022:"DEC     TZ89     (C) DECCX942S6295"

Note that the overall WWID consists of everything to the right of the equals sign. Each such WWID is unique; however, the header portion may not be unique, because the header reflects only the basic type and length of the WWID data.

The IO FIND_WWID command automatically records the information about the new tape devices in SYS$SYSTEM:SYS$DEVICES.DAT:

$ TYPE SYS$SYSTEM:SYS$DEVICES.DAT 
! 
! Updated 23-OCT-2000 14:17:41.85:  DEC TL800 
! 
[Device $2$GGA0] 
WWID=04100024:"DEC     TL800    (C) DEC3G9CCR82A017" 
! 
! 
! Updated 23-OCT-2000 14:17:41.93:  DEC TZ89 
! 
[Device $2$MGA0] 
WWID=04100022:"DEC     TZ89     (C) DECCX939S2777" 
! 
! 
! Updated 23-OCT-2000 14:17:42.01:  DEC TZ89 
! 
[Device $2$MGA1] 
WWID=04100022:"DEC     TZ89     (C) DECCX942S6295" 
!

Next, the SYSMAN command IO AUTOCONFIGURE configures the tape device.

$ MCR SYSMAN IO AUTOCONFIGURE/LOG 
 
%SYSMAN-I-OUTPUT, command execution on node SAMPLE 
%IOGEN-I-PREFIX, searching for ICBM with prefix SYS$ 
%IOGEN-I-PREFIX, searching for ICBM with prefix DECW$ 
%IOGEN-I-SCSIPOLL, scanning for devices through SCSI port PKA0 
%IOGEN-I-SCSIPOLL, scanning for devices through SCSI port PKB0 
%IOGEN-I-FIBREPOLL, scanning for devices through FIBRE port PGA0 
%IOGEN-I-CONFIGURED, configured device GGA0 
%IOGEN-I-CONFIGURED, configured device MGA0 
%IOGEN-I-CONFIGURED, configured device MGA1

Finally, the SHOW DEVICE/FULL command displays the WWID of the tape device.

$ SHOW DEVICE/FULL $2$MG 
 
Magtape $2$MGA0: (SAMPLE), device type TZ89, is online, file-oriented device, 
   available to cluster, error logging is enabled, controller supports 
    compaction (compaction  disabled), device supports fastskip. 
 
   Error count                    0    Operations completed                  0 
   Owner process                 ""    Owner UIC                      [SYSTEM] 
   Owner process ID        00000000    Dev Prot            S:RWPL,O:RWPL,G:R,W 
   Reference count                0    Default buffer size                2048 
   WWID   04100022:"DEC     TZ89     (C) DECCX939S2777" 
   Density                  default    Format                        Normal-11 
   Allocation class               2 
 
   Volume status:  no-unload on dismount, position lost, odd parity. 
                                                                        
Magtape $2$MGA1: (SAMPLE), device type TZ89, is online, file-oriented device, 
  available to cluster, error logging is enabled, controller supports 
    compaction (compaction  disabled), device supports fastskip. 
 
   Error count                    0    Operations completed                  0 
   Owner process                 ""    Owner UIC                      [SYSTEM] 
   Owner process ID        00000000    Dev Prot            S:RWPL,O:RWPL,G:R,W 
   Reference count                0    Default buffer size                2048 
   WWID   04100022:"DEC     TZ89     (C) DECCX942S6295" 
   Density                  default    Format                        Normal-11 
   Allocation class               2 
 
   Volume status:  no-unload on dismount, position lost, odd parity.

The F$GETDVI lexical function also retrieves the displayable WWID:

$ write sys$output f$getdvi("$2$MGA0","WWID") 
04100022:"DEC     TZ89     (C) DECCX939S2777"

Once the device is named and configured, you can use the device in the same way that you use parallel SCSI tapes with DCL commands such as INITIALIZE, MOUNT, BACKUP, and COPY. Refer to the installation guide for individual tape layered products for details on product-specific support of Fibre Channel tapes.

Note that while medium changers on Fibre Channel are autoconfigured, the medium changers on parallel SCSI continue to require the IO CONNECT command to load the device driver. It is impossible to manually connect a Fibre Channel medium changer by the SYSMAN IO CONNECT command because the device name does not imply the device's physical location, as it does in parallel SCSI.

7.5.4.3 Creating User-Specified Device Names

If you prefer to choose specific names for the tape devices instead of using the default names generated by IO FIND_WWID, you can use the IO CREATE_WWID command. For example:

SYSMAN > IO CREATE_WWID $2$MGA3/WWID=04100022:"DEC   TZ89   (C) DECCX939S2341"

The selected name must be of the form $2$GGAn for medium changers and $2$MGAn for tapes, where n is less than or equal to 32767. The name must not be in use elsewhere in the cluster. The WWID should be cut and pasted from the output of the IO LIST_WWID display. The IO CREATE_WWID command is intended only for naming new devices; it should not be used to rename existing devices. (Renaming existing devices is discussed in Section 7.5.5.)

The following configuration example uses IO CREATE_WWID to create user-specified device names for two tapes and a medium changer within an ESL library. The commands are executed clusterwide on a 2-node cluster consisting of nodes SYSTM1 and SYSTM2. Each node has two Fibre Channel host bus adapters, PGA0 and PGB0, so multiple paths to the tape are configured.

First, the SYSMAN command IO LIST_WWID displays a list of all previously undiscovered tape devices.

Systm1> mcr sysman 
SYSMAN> set env/clus 
%SYSMAN-I-ENV, current command environment: 
        Clusterwide on local cluster 
        Username SYSTEM       will be used on nonlocal nodes 
 
SYSMAN> io list_wwid 
 
%SYSMAN-I-OUTPUT, command execution on node SYSTM2 
On port _SYSTM2$PGA0:, the following tape WWIDs are not yet configured: 
 
Target 8, LUN 1, HP       ESL9000 Series 
WWID=0C000008:0050-8412-9DA1-0026 
 
Target 8, LUN 2, COMPAQ   SDLT320 
WWID=02000008:500E-09E0-0009-84D1 
 
Target 8, LUN 3, COMPAQ   SDLT320 
WWID=02000008:500E-09E0-0009-4E4E 
 
On port _SYSTM2$PGB0:, the following tape WWIDs are not yet configured: 
 
Target 6, LUN 1, HP       ESL9000 Series 
WWID=0C000008:0050-8412-9DA1-0026 
 
Target 6, LUN 2, COMPAQ   SDLT320 
WWID=02000008:500E-09E0-0009-84D1 
 
Target 6, LUN 3, COMPAQ   SDLT320 
WWID=02000008:500E-09E0-0009-4E4E 
 
%SYSMAN-I-OUTPUT, command execution on node SYSTM1 
On port _SYSTM1$PGA0:, the following tape WWIDs are not yet configured: 
 
 
Target 6, LUN 1, HP       ESL9000 Series 
WWID=0C000008:0050-8412-9DA1-0026 
 
Target 6, LUN 2, COMPAQ   SDLT320 
WWID=02000008:500E-09E0-0009-84D1 
 
Target 6, LUN 3, COMPAQ   SDLT320 
WWID=02000008:500E-09E0-0009-4E4E 
 
 
On port _SYSTM1$PGB0:, the following tape WWIDs are not yet configured: 
 
 
Target 5, LUN 1, HP       ESL9000 Series 
WWID=0C000008:0050-8412-9DA1-0026 
 
Target 5, LUN 2, COMPAQ   SDLT320 
WWID=02000008:500E-09E0-0009-84D1 
 
Target 5, LUN 3, COMPAQ   SDLT320 
WWID=02000008:500E-09E0-0009-4E4E 
 
 
%SYSMAN-I-NODERR, error returned from node SYSTM1 
-SYSTEM-W-NOMORENODE, no more nodes 
SYSMAN>

The previous NOMORENODE error is normal, because the command has completed on all existing nodes. Next, still in the same SYSMAN session, the user executes IO CREATE_WWID to choose device names $2$GGA40, $2$MGA40, $2$MGA41.

 
SYSMAN> io create_wwid $2$GGA40/WWID=0C000008:0050-8412-9DA1-0026 
%SYSMAN-I-NODERR, error returned from node SYSTM1 
-SYSTEM-W-NOMORENODE, no more nodes 
SYSMAN> io create_wwid $2$mga40/WWID=02000008:500E-09E0-0009-84D1 
%SYSMAN-I-NODERR, error returned from node SYSTM1 
-SYSTEM-W-NOMORENODE, no more nodes 
SYSMAN> io create_wwid $2$mga41/WWID=02000008:500E-09E0-0009-4E4E 
%SYSMAN-I-NODERR, error returned from node SYSTM1 
-SYSTEM-W-NOMORENODE, no more nodes 
SYSMAN>

The user now executes IO AUTOCONFIGURE to configure the devices. Note that both the PGA path and the PGB path are configured for each node.

 
 
SYSMAN> io auto/lo 
 
%SYSMAN-I-OUTPUT, command execution on node SYSTM2 
%IOGEN-I-PREFIX, searching for ICBM with prefix SYS$ 
%IOGEN-I-PREFIX, searching for ICBM with prefix DECW$ 
%IOGEN-I-FIBREPOLL, scanning for devices through FIBRE port PGA0 
%IOGEN-I-CONFIGURED, configured device GGA40 
%IOGEN-I-CONFIGURED, configured device MGA40 
%IOGEN-I-CONFIGURED, configured device MGA41 
%IOGEN-I-FIBREPOLL, scanning for devices through FIBRE port PGB0 
%IOGEN-I-CONFIGURED, configured device GGA40 
%IOGEN-I-CONFIGURED, configured device MGA40 
%IOGEN-I-CONFIGURED, configured device MGA41 
 
%SYSMAN-I-OUTPUT, command execution on node SYSTM1 
%IOGEN-I-PREFIX, searching for ICBM with prefix SYS$ 
%IOGEN-I-PREFIX, searching for ICBM with prefix DECW$ 
%IOGEN-I-FIBREPOLL, scanning for devices through FIBRE port PGA0 
%IOGEN-I-CONFIGURED, configured device GGA40 
%IOGEN-I-CONFIGURED, configured device MGA40 
%IOGEN-I-CONFIGURED, configured device MGA41 
%IOGEN-I-FIBREPOLL, scanning for devices through FIBRE port PGB0 
%IOGEN-I-CONFIGURED, configured device GGA40 
%IOGEN-I-CONFIGURED, configured device MGA40 
%IOGEN-I-CONFIGURED, configured device MGA41 
%SYSMAN-I-NODERR, error returned from node SYSTM1 
-SYSTEM-W-NOMORENODE, no more nodes 
SYSMAN> exit 
Systm1> 
Systm1>SHOW DEVICE/FULL $2$GG 
 
Device $2$GGA40:, device type Generic SCSI device, is online, shareable, device 
    has multiple I/O paths. 
 
    Error count                    0    Operations completed                  0 
    Owner process                 ""    Owner UIC                      [SYSTEM] 
    Owner process ID        00000000    Dev Prot    S:RWPL,O:RWPL,G:RWPL,W:RWPL 
    Reference count                0    Default buffer size                   0 
    WWID   0C000008:0050-8412-9DA1-0026 
 
  I/O paths to device              2 
  Path PGA0.1000-00E0-0242-86ED (SYSTM1), primary path, current path. 
    Error count                    0    Operations completed                  0 
  Path PGB0.1000-00E0-0222-86ED (SYSTM1). 
    Error count                    0    Operations completed                  0 
 
Systm1> sho dev/fu $2$MG 
 
Magtape $2$MGA40: (SYSTM1), device type COMPAQ SDLT320, is online, file-oriented 
    device, available to cluster, device has multiple I/O paths, error logging 
    is enabled, device supports fastskip (per_io). 
 
    Error count                    0    Operations completed                  2 
    Owner process                 ""    Owner UIC                      [SYSTEM] 
    Owner process ID        00000000    Dev Prot            S:RWPL,O:RWPL,G:R,W 
    Reference count                0    Default buffer size                2048 
    WWID   02000008:500E-09E0-0009-84D1 
    Density                  default    Format                        Normal-11 
    Host name               "SYSTM1" Host type, avail AlphaServer DS10 466 MHz, yes 
    Alternate host name     "SYSTM2" Alt. type, avail AlphaServer DS10 466 MHz,  no 
    Allocation class               2 
 
  Volume status:  no-unload on dismount, position lost, odd parity. 
 
  I/O paths to device              2 
  Path PGA0.1000-00E0-0242-86ED (SYSTM1), primary path, current path. 
    Error count                    0    Operations completed                  1 
  Path PGB0.1000-00E0-0222-86ED (SYSTM1). 
    Error count                    0    Operations completed                  1 
 
 
Magtape $2$MGA41: (SYSTM1), device type COMPAQ SDLT320, is online, file-oriented 
    device, available to cluster, device has multiple I/O paths, error logging 
    is enabled, device supports fastskip (per_io). 
 
    Error count                    0    Operations completed                  0 
    Owner process                 ""    Owner UIC                      [SYSTEM] 
    Owner process ID        00000000    Dev Prot            S:RWPL,O:RWPL,G:R,W 
    Reference count                0    Default buffer size                2048 
    WWID   02000008:500E-09E0-0009-4E4E 
    Density                  default    Format                        Normal-11 
    Host name               "SYSTM1" Host type, avail AlphaServer DS10 466 MHz, yes 
    Alternate host name     "SYSTM2" Alt. type, avail AlphaServer DS10 466 MHz,  no 
    Allocation class               2 
 
  Volume status:  no-unload on dismount, position lost, odd parity. 
 
  I/O paths to device              2 
  Path PGA0.1000-00E0-0242-86ED (SYSTM1), primary path, current path. 
    Error count                    0    Operations completed                  0 
  Path PGB0.1000-00E0-0222-86ED (SYSTM1). 
    Error count                    0    Operations completed                  0 
 
Systm1>

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