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The default value of 7 preserves compatibility with existing DECwindows Motif behavior. A value of 0 disables all unevaluated configurations.
Specify one of the following values:
| Value | Description |
|---|---|
| 0 | No shadowing is enabled; SHDRIVER is not loaded. This is the default value. |
| 2 | Host-based volume shadowing enabled; SHDRIVER is loaded. Host-based volume shadowing provides shadowing of all disks located on a standalone system or an OpenVMS Cluster system. |
The reset threshold is specified by the RESET_THRESHOLD keyword in the /POLICY qualifier of the SET SHADOW command.
When the comparison is made, the modified block count might exceed the reset threshold by a small increment or by a much larger amount. The difference depends on the write activity to the volume and on the setting of this parameter.
Carefully consider the needs of each shadowed node when you set this parameter. Too high a value for SHADOW_MAX_COPY can affect performance by allowing too many copy threads to operate in parallel. Too low a value unnecessarily restricts the number of threads your system can effectively handle.
See HP Volume Shadowing for OpenVMS for more information about setting system parameters for volume shadowing.
Review this default carefully. The setting must be equal to or greater than the number of shadow sets you plan to have on a system. If you attempt to mount more shadow sets than the number specified by SHADOW_MAX_UNIT, the MOUNT command will fail. Dismounted shadow sets, unused shadow sets, and shadow sets with no write bitmaps allocated to them are included in the count for SHADOW_MAX_UNIT. |
On Alpha and Integrity servers, the default value for this system parameter is 500, which consumes 24 KB of main memory.
If you do not plan to use Volume Shadowing for OpenVMS, you can change the setting to its minimum of 10 (which consumes 480 bytes of main memory). Setting the default to its minimum frees up 23.5 KB of main memory on an OpenVMS Alpha or Integrity servers and 4.5 KB of main memory on a VAX system. (The maximum value of this parameter is 10,000.)
This system parameter is not dynamic; that is, a reboot is required when you change the setting.
The SHADOW_MBR_TMO parameter is valid for use only with Phase II of Volume Shadowing for OpenVMS. You cannot set this parameter for use with Phase I, which is obsolete.
Use the SHADOW_MBR_TMO parameter (a word) to specify the number of seconds, in decimal from 1 to 65,535, during which recovery of a repairable shadow set is attempted. If you do not specify a value or if you specify 0, the default delay of 120 seconds is used.
Because SHADOW_MBR_TMO is a dynamic parameter, you should use the SYSGEN command WRITE CURRENT to permanently change its value.
SHADOW_PSM_RDLY allows the system manager to adjust the delay that shadowing adds. By default, the delay is 30 seconds for each MSCP-served shadow set member. The valid range for the specified delay is 0 through 65,535 seconds.
When a shadow set is mounted on a system, the value of SHADOW_PSM_RDLY is used as the default shadow set member recovery delay for that shadow set. To modify SHADOW_PSM_RDLY for an existing shadow set, see the SET SHADOW/ /RECOVERY_OPTIONS=DELAY_PER_SERVED_MEMBER=n command in HP Volume Shadowing for OpenVMS.
The value of the SHADOW_REC_DLY parameter specifies the length of time a system waits before it attempts to manage recovery operations on shadow sets that are mounted on the system. A shadow set is said to need recovery when a merge or copy operation is required on that shadow set.
SHADOW_REC_DLY can be used to better predict which systems in an OpenVMS Cluster performs recovery operations. This is done by setting lower values of SHADOW_REC_DLY on systems that are preferred to handle recovery operations and higher values of SHADOW_REC_DLY on systems that are least preferred to handle recovery operations.
The range of SHADOW_REC_DLY is 20 to 65535 seconds. The default value is 20 seconds.
For more information about controlling which systems perform the merge or copy operations, see HP Volume Shadowing for OpenVMS.
The system manager can now define the site value to be used for all shadow sets mounted on a system. This parameter is an arbitrary numeric value coordinated by the system manager of disaster tolerant clusters. Reads from devices that have site values matching the shadow set's site value are preferred over reads from devices with different site values. For detailed information, see the description of the $SET DEVICE/SITE in the HP OpenVMS DCL Dictionary and HP Volume Shadowing for OpenVMS.
Also specify a system disk shadow set virtual unit number with the SHADOW_SYS_UNIT system parameter, unless the desired system disk unit number is DSA0.
A value of 4096 enables CI-based minimerge. To enable minimerge on a system disk, however, you must enable DOSD by setting the DUMPSTYLE parameter to dump off system disk, as described in the HP OpenVMS System Manager's Manual. You can then add the value 4096 to your existing SHADOW_SYS_DISK value. For example, if you have SHADOW_SYS_DISK set to a value of 1, change it to 4097 to enable minimerge.
This parameter applies only to members of the system disk shadow set. All nodes using a particular system disk shadow set should have their SHADOW_SYS_TMO parameter set to the same value once normal operations begin.
The default value is 120 seconds. Change this parameter to a higher value if you want the system to wait more than the 120-second default for all members to join the shadow set. You can set the parameter value to 120 through 65,535 seconds.
The default value is 480 seconds. Change this parameter to a higher value if you want the system to wait more than the 480-second default for all members to join the shadow set. You can set the parameter value to 1 through 65,535 seconds.
Bits in the bit mask are the following:
| Bit | Mask | Description | |
|---|---|---|---|
| 0 | 0 | 0 = | Do not create local communications channels (SYSGEN default). Local SCS communications are primarily used in test situations and are not needed for normal operations. Not creating local communications saves resources and overhead. |
| 1 = | Create local communications channels. | ||
| 1 | 2 | 0 = | Load SYS$PBDRIVER if booting into both a Galaxy and a Cluster (SYSGEN Default). |
| 1 = | Load SYS$PBDRIVER if booting into a Galaxy. | ||
| 2 | 4 | 0 = | Minimal console output (SYSGEN default). |
| 1 = | Full console output; SYS$PBDRIVER displays console messages when it creates and tears down communications channels. | ||
Loading additional ports allows multiple paths between Galaxy instances. In the initial release of the Galaxy software, having multiple communications channels is not an advantage because SYS$PBDRIVER does not support fast path. A future release of OpenVMS will provide Fast Path support for SYS$PBDRIVER, when multiple CPUs improve throughput by providing multiple communications channels between instances.
SMP_CPU_BITMAP defaults to all bits set. (CPU 0 through CPU 1023 are enabled for multiprocessing.) Note that the primary processor is always booted regardless of the setting of the corresponding bit in the CPU bitmap.
To change the value of SMP_CPU_BITMAP in SYSBOOT or SYSGEN, specify a list of individual bits or contiguous groups of bits. For example:
SYSGEN> SET SMP_CPU_BITMAP 0,5,17-21 |
The command in this example sets bits 0, 5, 17, 18, 19, 20, and 21 in the bitmap and clears all other bits.
This parameter replaces the SMP_CPUS parameter.
Generally spinlocks at IPL <= 8 have long holding times, therefore have their timeout intervals set to SMP_LNGSPINWAIT to prevent SPINWAIT timeouts in cases of nested acquisition.
A timeout causes a CPUSPINWAIT bugcheck.
The default value is 3000000 (30,00, 000 10-microsecond intervals or 30 second).
The default value is 300 milliseconds (30 10-millisecond intervals).
A timeout causes a CPUSPINWAIT bugcheck.
The default value is 100000 (100,000 10-microsecond intervals or 1 second).
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
System Service Interception is a mechanism that allows user specified code to run before, after or instead of the intercepted system service. This mechanism is available on OpenVMS Alpha Version 6.1 and later and OpenVMS Integrity servers Version 8.3 and later, but the parameter SSI_ENABLE is relevant only on Integrity server systems.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
| STARTUP Value | Description |
|---|---|
| STARTUP_P1 |
Specifies the type of system boot the system-independent startup
procedure is to perform when STARTUP_P1 has one of the following values:
|
| STARTUP_P2 |
Controls the setting of verification during the execution of the
system-independent startup procedure, STARTUP.COM, when STARTUP_P2 has
one of the values described in the lists below.
STARTUP_P2 can be one of the values shown in the following list:
Alternatively, STARTUP_P2 can be a string containing one or more of the letters shown in the following list:
For more information about STARTUP_P2, see the SYSMAN command STARTUP SET OPTIONS. |
| STARTUP_P3 | Beginning in OpenVMS Version 7.2, if STARTUP_P3 is set to AGEN, the system executes AUTOGEN at the end of the startup sequence. |
|
STARTUP_P4
through STARTUP_P8 |
Reserved for future use. |
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
On Alpha and Integrity servers, SWPOUTPGCNT defines the minimum number of pagelets to which the swapper should attempt to reduce a process before swapping it out. The pagelets taken from the process are placed into the free-page list.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
While a high value takes space away from user working sets, a low value can seriously impair system performance. Appropriate values vary, depending on the level of system use. When the system is running at full load, check the rate of system faults with the MONITOR PAGE command of the Monitor utility. An average system page fault rate of between 0 and 3 page faults per second is desirable. If the system page fault rate is high, and especially if the system seems to be slow, you should increase the value of SYSMWCNT. However, do not set this parameter so high that system page faulting never occurs.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
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$LOADABLE_IMAGES and can be identified by the suffix _MON. For information about the type of data checking performed by SYSTEM_CHECK, see the description of the ACP_DATACHECK parameter. For information about the performance implications of enabling SYSTEM_CHECK, see OpenVMS Performance Management.
The TAPE_ALLOCLASS parameter can also be used to generate a unique clusterwide name for tape devices with identical unit numbers.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
TIME_CONTROL is an SMP bit mask parameter that controls debugging functions. The following bits are defined:
| Bit | Description |
|---|---|
| 0 | Obsolete. |
| 1 (EXE$V_SANITY) | Disables the SMP sanity timer support. |
| 2 (EXE$V_NOSPINWAIT) | Disables the functional behavior of the SMP spinwait support. |
HP recommends that you set the correct system time before allowing the system to run, so that all functions using time-stamping (such as the operator log, the error log, accounting records, file creation dates, and file expiration dates) contain correct time values. |
Depending on the value specified for the TIMEPROMPTWAIT parameter, the system acts in one of the following ways:
Setting TMSCP_LOAD to 0 inhibits the loading of the tape server and the serving of local tapes. Setting TMSCP to 1 loads the tape server into memory at the time the system is booted and makes all directly connected tape drives available clusterwide. The following table describes the two states of the TMSCP_LOAD parameter:
| State | Function |
|---|---|
| 0 | Do not load the TMSCP tape server. Do not serve any local tape devices clusterwide. This is the default value. |
| 1 | Load the TMSCP tape server. Serve all local TMSCP tape devices clusterwide. |
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