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sda_-_how_do_i_find_who_is_trying_to_allocate_or_deallocate_nonpaged_pool [2019/02/12 19:54] (current)
mmacgregor created
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 +==== Introduction ====
 +You notice that NONPAGED POOL expansion has been occurring on the system. ​ How would you determine who has done the most recent allocations?​
 +==== Details ====
 +First you will need to have one of these two SYSGEN parameters enabled. ​ SYSTEM_CHECK or POOLCHECK.
 +       ​SYSTEM_CHECK investigates intermittent system failures by
 +       ​enabling a number of run-time consistency checks on system
 +       ​operation and recording some trace information.
 +       ​Enabling SYSTEM_CHECK causes the system to behave as if the
 +       ​following system parameter values are set (although the values
 +       of the following parameters are not actually changed):
 +       ​Parameter ​       Value         ​Description
 +       ​BUGCHECKFATAL ​   1             Crash the system on nonfatal
 +                                      bugchecks.
 +       ​POOLCHECK ​       %X616400FF ​   Enable all poolchecking,​ with
 +                                      an allocated pool pattern
 +                                      of %x61616161 ('​aaaa'​) and
 +                                      deallocated pool pattern of
 +                                      x64646464 ('​dddd'​).
 +       ​MULTIPROCESSING ​ 2             ​Enable full synchronization
 +                                      checking.
 +       While SYSTEM_CHECK is enabled, the previous settings of the
 +       ​BUGCHECKFATAL and MULTIPROCESSING parameters are ignored.
 +       ​However,​ setting the parameter POOLCHECK to a nonzero value
 +       ​overrides the setting imposed by SYSTEM_CHECK.
 +       ​Setting SYSTEM_CHECK creates certain image files that are capable
 +       of the additional system monitoring. These image files are
 +       ​located in SYS$LOADABLE_IMAGES and can be identified by the
 +       ​suffix _MON. For information about the type of data checking
 +       ​performed by SYSTEM_CHECK,​ see the description of the ACP_
 +       ​DATACHECK parameter. For information about the performance
 +       ​implications of enabling SYSTEM_CHECK,​ see OpenVMS Performance
 +       ​Management.
 +       </​code>​
 +       This special parameter is used by HP and is subject to change. Do
 +       not change this parameter unless HP recommends that you do so.
 +       ​POOLCHECK is used to investigate frequent and inexplicable
 +       ​failures in a system. When POOLCHECK is enabled, pool-checking
 +       ​routines execute whenever pool is deallocated or allocated.
 +       Two loadable forms of SYSTEM_PRIMITIVES.EXE are available at
 +       boot time. The default image, which contains no pool-checking
 +       code and no statistics maintenance,​ is loaded when POOLCHECK
 +       is set to zero. When POOLCHECK is set to a nonzero value, the
 +       ​monitoring version of SYSTEM_PRIMITIVES.EXE,​ which contains both
 +       ​pool-checking code and statistics maintenance,​ is loaded.
 +       ​Setting the SYSTEM_CHECK parameter to 1 has the effect of setting
 +       ​POOLCHECK to %X616400FF. For further information about pool
 +       ​checking,​ see the OpenVMS VAX Device Support Manual, (which is
 +       ​archived).
 +       ​POOLCHECK is a DYNAMIC parameter. However, for a change in its
 +       value to have any effect, POOLCHECK must be non-0 at boot time
 +       (to load the monitoring version of SYSTEM_PRIMITIVES.EXE).</​code>​
 +NOTE:  SYSTEM_CHECK is not dynamic and would require a system reboot to take effect. ​ POOLCHECK is dynamic and can be enabled on the live system.
 +Booting the system with POOLCHECK non-zero or SYSTEM_CHECK = 1 loads the monitoring version of the system_primitives loadable image. This records allocations/​deallocations of nonpaged pool in a ring buffer whose size is controlled by the SYSGEN parameter NPAG_RING_SIZE. This recording takes place regardless of the pool poisoning/​checking enabled bits in the lower bit positions of the poolcheck parameter. To display these allocations/​deallocations use this command:
sda_-_how_do_i_find_who_is_trying_to_allocate_or_deallocate_nonpaged_pool.txt ยท Last modified: 2019/02/12 19:54 by mmacgregor