HP OpenVMS Systems Documentation

If your system fails, make a copy of the contents of the system dump file and contact your Compaq support representative. You can use the Backup utility (BACKUP) to create save sets containing system dump files on magnetic tape or disk. However, when using BACKUP to copy system dump files, you must specify the /IGNORE=(NOBACKUP,INTERLOCK) qualifier for the following reasons:

• By default, the system dump file has the NOBACKUP attribute, so it is not copied unless you specify /IGNORE=NOBACKUP.
• The system keeps an open channel to the system dump file, so the file is not copied unless you specify /IGNORE=INTERLOCK.

Compaq recommends that you use the following procedure to copy your system dump file:

1. Use the SDA command COPY to make a copy of the system dump file.
2. Use BACKUP to save that copy on tape or disk.

This procedure avoids issues with BACKUP qualifiers and reduces the amount of data written to tape or disk because the SDA command COPY copies only blocks in the system dump file that are actually used.

16.13 Freeing Dump Information from the Page File

If you use SYS$SYSTEM:PAGEFILE.SYS to store a system crash dump, you must later free the space occupied by the system dump for use by the pager. If you do not, your system might hang because of insufficient paging space.

Section 16.1.1 explains when you might use the page file to store a system crash dump.

16.13.1 Freeing Dump Information on VAX and Alpha Systems

This section contains instructions for freeing dump information from the page file on VAX and Alpha systems.

How to Perform This Task on VAX Systems

On VAX systems, perform the following steps:

1. Invoke the System Dump Analyzer utility (SDA), specifying PAGEFILE.SYS as the target:

   $ ANALYZE/CRASH_DUMP SYS$SYSTEM:PAGEFILE.SYS

2. Enter the SDA command COPY in the following format to copy the dump from SYS$SYSTEM:PAGEFILE.SYS to another file:

   COPY dump_filespec

   
   For example, to copy the system dump file off the system disk to a file called SAVEDUMP.DMP on DISK$USER5, enter the following command:

   SDA> COPY DISK$USER5:[DUMPS]SAVEDUMP.DMP

3. Enter the EXIT command to exit SDA.
4. Include the SDA commands entered in steps 1 and 2 in the site-specific startup command procedure SYSTARTUP_VMS.COM to free page space each time the system reboots.

Alternatively, to free the pages in the page file that are taken up by the dump without having to copy the dump elsewhere, enter the ANALYZE/CRASH_DUMP/RELEASE command. This command immediately releases the pages to be used for system paging, effectively deleting the dump. Note that this command does not allow you to analyze the dump before deleting it.

Example

The following commands, added to the SYSTARTUP_VMS.COM command procedure, copy the contents of the page file to a file named SAVEDUMP.DMP:

$ ANALYZE/CRASH_DUMP SYS$SYSTEM:PAGEFILE.SYS
  COPY DISK$USER5:[DUMPS]SAVEDUMP.DMP
  EXIT
$ SET FILE/NOBACKUP SYS$SYSTEM:SAVEDUMP.DMP

How to Perform This Task on Alpha Systems

On Alpha systems, as described in the OpenVMS Alpha System Analysis Tools Manual, SDA is automatically invoked by default when the system is rebooted after a system failure.

To automatically save the system dump file, perform the following steps:

1. Create a SYS$$MANAGER:SAVEDUMP.COM file; for example:

   ! ! SDA command file, to be executed as part of the system ! bootstrap from within CLUE. Commands in this file can ! be used to save the dump file after a system bugcheck, and ! to execute any additional SDA command. ! READ/EXEC ! Read in the executive images' symbol tables SHOW STACK ! Display the stack COPY SAVEDUMP.DMP ! Copy and save system dump file !

2. To point to your site-specific file, add a line such as the following one to the file SYS$MANAGER:SYLOGICALS.COM:

   $ DEFINE/SYSTEM CLUE$SITE_PROC SYS$MANAGER:SAVEDUMP.COM

   
   In this example, the site-specific file is named SAVEDUMP.COM.

If the logical CLUE$INHIBIT has been defined, and SDA has not been automatically invoked during system startup, the pages in the page file that are taken up by the dump can be released using the ANALYZE/CRASH_DUMP/RELEASE command. This command immediately releases the pages to be used for system paging, effectively deleting the dump. Note that this command does not allow you to analyze the dump before deleting it.

For a discussion of logical names used by CLUE, refer to OpenVMS Alpha System Analysis Tools Manual.

16.13.2 Usage Notes for Freeing Information on VAX and Alpha Systems

Because a system dump file can contain privileged information, protect copies of dump files from world read access.

To prevent the system from backing up the complete contents of the file, assign the NOBACKUP attribute to the file with the DCL command SET FILE/NOBACKUP.

Although you can also use the DCL command COPY to copy a dump file, Compaq recommends that you use the SDA command COPY because SDA COPY performs the following actions:

• Copies only the blocks that the dump actually occupies.
• Releases for paging the pages that the dump occupies in the system's page file.

The system automatically installs the primary page and swap files located in SYS$SYSTEM. However, other page and swap files are not automatically installed. For this reason, if you create secondary page and swap files, you must also install them with the System Generation utility (SYSGEN). Note that SYSGEN INSTALL commands perform a different function than Install utility (INSTALL) commands.

16.14.1 Installing Interactively

1. Invoke SYSGEN by entering the following command:

   $ RUN SYS$SYSTEM:SYSGEN

2. Enter the SYSGEN command INSTALL as follows:
   For page files, use the following format:

   INSTALL file-spec/PAGEFILE

   
   For example:

   SYSGEN> INSTALL DUA2:[PAGE_SWAP]PAGEFILE_1.SYS/PAGEFILE

   
   For swap files, use the following format:

   INSTALL file-spec/SWAPFILE

   
   For example:

   SYSGEN> INSTALL DUA2:[PAGE_SWAP]SWAPFILE_1.SYS/SWAPFILE

3. To make sure the files are installed each time the system boots, edit SYS$MANAGER:SYPAGSWPFILES.COM to add the commands you entered in step 2. For more information, see Section 16.14.2.

Example

The following example installs page and swap files interactively:

$ RUN SYS$SYSTEM:SYSGEN
SYSGEN> INSTALL DUA2:[PAGE_SWAP]PAGEFILE_1.SYS/PAGEFILE
SYSGEN> INSTALL DUA2:[PAGE_SWAP]SWAPFILE_1.SYS/SWAPFILE

Page and swap files other than SYS$SYSTEM:PAGEFILE.SYS and SYS$SYSTEM:SWAPFILE.SYS must be reinstalled each time the system boots. You can do this by adding the commands to install the files to the startup command procedure SYS$MANAGER:SYPAGSWPFILES.COM. The template file SYS$MANAGER:SYPAGSWPFILES.TEMPLATE includes comments that help explain how this file is used.

Before performing this task, you must have created the secondary files, as explained in Section 16.16.

For more information about SYPAGSWPFILES.COM, see Section 5.2.3.

You can also use SATELLITE_PAGE.COM to install page and swap files on an OpenVMS Cluster satellite node's local disk. SATELLITE_PAGE.COM is created when you run CLUSTER_CONFIG.COM. For more information about installing page and swap files on a satellite node's local disk, refer to the OpenVMS Cluster Systems manual.

How to Perform This Task

1. Invoke any editor to edit SYS$MANAGER:SYPAGSWPFILES.COM.
2. If necessary, add a MOUNT command for each disk that holds a page or swap file. This is necessary because only the system disk is mounted at the time SYPAGSWPFILES.COM is invoked.
   For example:

   $ MOUNT/SYSTEM/NOASSIST DUA2: DISK_SYS2

   
   For information about the MOUNT command, refer to the OpenVMS DCL Dictionary.
   The following commands, inserted before the MOUNT command, are also useful to determine if the disk is available before mounting. Note, however, that if the disk is broken and cannot mount, these commands will cause an infinite loop.

   $ LOOP1: $ ON WARNING THEN GOTO LOOP1 $ WAIT 0000 00:00:00.50 $ READY = F$GETDVI("device:","AVL") $ IF READY .EQS. "FALSE" THEN GOTO LOOP1

   
   where device: specifies the device name.
3. Add the following command to invoke SYSGEN:

   $ RUN SYS$SYSTEM:SYSGEN

4. Add commands in the following format to SYPAGSWPFILES.COM to install the files each time the system boots.
   For page files, use the following format:

   INSTALL file-spec/PAGEFILE

   
   For example:

   INSTALL DUA2:[SYSTEM]PAGEFILE_1.SYS/PAGEFILE

   
   For swap files, use the following format:

   INSTALL file-spec/SWAPFILE

   
   For example:

   INSTALL DUA2:[SYSTEM]SWAPFILE_1.SYS/SWAPFILE

5. Add an EXIT command to exit SYSGEN:

   EXIT

Example

The following example shows commands you might add to SYPAGSWPFILES.COM to install page and swap files named PAGEFILE_1.SYS and SWAPFILE_1.SYS located on the DUA2: device:

$ EDIT SYS$MANAGER:SYPAGSWPFILES.COM
  [add the following commands to SYPAGSWPFILES.COM:]
   .
   .
   .

$ MOUNT/SYSTEM/NOASSIST DUA2: DISK_SYS2
$ RUN SYS$SYSTEM:SYSGEN
  INSTALL DUA2:[SYSTEM]PAGEFILE_1.SYS /PAGEFILE
  INSTALL DUA2:[SYSTEM]SWAPFILE_1.SYS /SWAPFILE
  EXIT

How to Perform This Task

1. Use the RENAME command to rename the file to be deleted.
2. Shut down and reboot the system.
3. Delete the file.
4. When you delete a file, make sure you remove from SYPAGSWPFILES.COM and MODPARAMS.DAT any command lines related to the file.

Example

$ RENAME DUA2:[SYSTEM]PAGEFILE_1.SYS; DUA2:[SYSTEM]JUNK.SYS;
$ @SYS$SYSTEM:SHUTDOWN.COM
   .
   .
   .
[SHUTDOWN.COM shuts down and reboots the system]
[When the system reboots, log in]
   .
   .
   .
$ DELETE DUA2:[SYSTEM]JUNK.SYS;

For performance or disk space reasons, you might want to create system page, swap, and dump files on disks other than the system disk. (Error log dump files, however, must remain on the system disk.)

The following sections explain how to perform this task:

You can direct AUTOGEN to create new system page, swap, and dump files by adding symbols to MODPARAMS.DAT to specify the name, location, and size of new files to be created and then running AUTOGEN. Before performing this task, you should understand AUTOGEN and its parameter file MODPARAMS.DAT. For more information about when to use AUTOGEN, see Section 15.4. See Section 15.4.4 for information about MODPARAMS.DAT.

AUTOGEN automatically calculates appropriate sizes for system page, swap, and dump files. It also modifies the files to the appropriate sizes and installs them. You can control sizes calculated by AUTOGEN by defining symbols in the file MODPARAMS.DAT. For more information, see Section 16.16.1.2.

How to Perform This Task

To change the sizes of system page, swap, and dump files, execute AUTOGEN in two passes as follows:

1. Enter the following command to invoke a first pass of AUTOGEN. AUTOGEN displays its calculations for system file sizes to SYS$OUTPUT:

   $ @SYS$UPDATE:AUTOGEN SAVPARAMS TESTFILES

2. If the file sizes displayed in step 1 are inadequate, add symbols to MODPARAMS.DAT to control the size of files as explained in Section 16.16.1.2 and return to step 1.
3. When you are satisfied with the file sizes displayed in step 1, execute a second pass of AUTOGEN using the following command to install the modified system files when the system is rebooted:

   $ @SYS$UPDATE:AUTOGEN GENPARAMS REBOOT

4. Add commands to the site-specific startup command procedure SYPAGSWPFILES.COM to make sure the files are installed each time the system boots. For instructions, see Section 16.14.

Add the following symbols to MODPARAMS.DAT to specify the names and locations of the page and swap files to be created:

where:

• n specifies the page or swap file. Refer to the primary page and swap files by specifying a value of 1 for n; refer to subsequent files by specifying increasingly higher integer values for n. For example, to refer to a secondary page or swap file, specify a value of 2 for n.
• file-spec specifies the full file specification of the file to be created.
• device specifies the disk name to be used.

You can add information to the AUTOGEN parameter file MODPARAMS.DAT to control the sizes that AUTOGEN calculates for system page, swap, and dump files. If you do not supply system file size information in MODPARAMS.DAT, AUTOGEN performs default size calculations for page, swap, and dump files.

You can define symbols in MODPARAMS.DAT to specify either of the following items:

For page and swap files, AUTOGEN generally manipulates the primary files SYS$SYSTEM:PAGEFILE.SYS and SYS$SYSTEM:SWAPFILE.SYS only if you have no other page and swap files. If you have secondary files, AUTOGEN manipulates the secondary files and excludes primary files. However, in some instances, AUTOGEN might modify the size of the primary page and swap files.

On VAX systems, for system dump files, AUTOGEN manipulates the size of only one file: the system dump file on the system disk if no DUMPFILE_DEVICE is given, or the system dump file on the specified device if DUMPFILE_DEVICE is specified.

On VAX systems, AUTOGEN always creates a minimal SYSDUMP.DMP file on the system disk for error log buffers if DUMPFILE_DEVICE is specified.

On Alpha systems, AUTOGEN only manipulates the size of the error log dump file on the system disk.

If you do not want AUTOGEN to change the sizes of the primary files, specify the following symbols in MODPARAMS.DAT:

PAGEFILE =   0
SWAPFILE =   0
DUMPFILE =   0
ERRLOGDUMP = 0 ! Alpha only

These symbols direct AUTOGEN to ignore the primary page, swap, and dump files when calculating sizes.

If the creation or extension of a system page, swap, or dump file would cause the target disk to become more than 95 percent full, AUTOGEN issues a warning and does not perform the operation.

On Alpha systems, however, the 95 percent rule does not apply to the error log dump file, SYS$ERRLOG.DMP. This file is created if the disk can hold it.

You can use AUTOGEN to create a page, swap, or dump file that is smaller than the current version of the file. After you have booted and begun using the new file, remember to use the DCL command PURGE to reclaim the disk space from the old version of the file.

To determine the current sizes of installed page and swap files, enter the DCL command SHOW MEMORY/FILES. If you increased the size of any of these files and have not rebooted, this command displays the original sizes. Use the DIRECTORY command to determine the size of dump files.

Table 16-4 lists the symbols you can define in MODPARAMS.DAT to control the total size of page file, swap file, system dump file, or error log dump file space space.

Table 16-5 lists the symbols you can define in MODPARAMS.DAT to control the size of individual files.