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HP OpenVMS systems documentation |
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The value of MC_SERVICES_P6 must be the same on all nodes connected by MEMORY CHANNEL.
The default value is 0. HP recommends that this value not be changed except while debugging MEMORY CHANNEL problems or adjusting the MC_SERVICES_P9 parameter.
Note that MC_SERVICES_P9 is not a dynamic parameter; you must reboot the system after each change for that change to take effect.
The default value is 150. HP recommends that this value not be changed.
The value of MC_SERVICES_P9 must be the same on all nodes connected by MEMORY CHANNEL.
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 VAX systems, MINWSCNT sets the minimum number of fluid pages (pages not locked in the working set) required for the execution of a process. The value of MINWSCNT must provide sufficient space to execute any VAX instruction. Theoretically, the longest instruction requires 52 pages; however, all code can run with 20 fluid pages. An insufficient value may inhibit system performance or even put a process into an infinite loop on some instructions.
On Alpha and I64 systems, MINWSCNT sets the minimum number of pages required for the execution of a process. The default value is 20; the minimum value is 10.
The first two bits, 0 and 1, control the proactive memory reclamation mechanisms. Bit 2 controls deferred memory testing.
The following bit mask values are defined:
| Bit | Description |
|---|---|
| 0 | If this bit is set, reclamation is enabled by trimming from periodically executing, but otherwise idle, processes. This occurs when the size of the free list drops below two times FREEGOAL. This function is disabled if the bit is clear. |
| 1 | If this bit is set, reclamation is enabled by outswapping processes that have been idle for longer than LONGWAIT seconds. This occurs when the size of the free list drops below FREEGOAL. This function is disabled if the bit is clear. |
| 2 |
Controls deferred memory testing (only on AlphaServer 4100 systems).
You can use this bit to speed up elapsed bootstrap time by controlling
when memory is tested:
|
| 3-7 | Reserved for future use. |
MPDEV_POLLER must be set to ON to enable automatic failback. You can disable automatic failback without disabling the poller by setting MPDEV_AFB_INTVL to 0. The default is 300 seconds.
MPDEV_REMOTE and MPDEV_AFB_INTVL have no effect when MPDEV_ENABLE is set to OFF.
To use multipath failover to a served path, MPDEV_REMOTE must be enabled on all systems that have direct access to shared SCSI/Fibre Channel devices. The first release to provide this feature is OpenVMS Alpha Version 7.3--1. Therefore, all nodes on which MPDEV_REMOTE is enabled must be running OpenVMS Alpha Version 7.3--1 (or later).
If MPDEV_ENABLE is set to OFF (0), the setting of MPDEV_REMOTE has no effect because the addition of all new paths to multipath sets is disabled. The default is ON.
If MPW_HILIMIT is too low, excessive page faulting can occur from the page file. If it is too high, too many physical pages can be consumed by the modified-page list.
If you increase MPW_HILIMIT, you might also need to increase MPW_WAITLIMIT. Note that if MPW_WAITLIMIT is less than MPW_HILIMIT, a system deadlock occurs. The values for the two parameters are usually equal.
MPW_LOLIMIT ensures that a certain number of pages are available on the modified-page list for page faults. If the number is too small, the caching effectiveness of the modified-page list is reduced. If it is too high, less memory is available for processes, so that swap (and page) may increase.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
If MPW_WRTCLUSTER is too small, it takes many I/O operations to empty the modified-page list. If MPW_WRTCLUSTER is too large for the speed of the disk that holds the page file, other I/O operations are held up for the modified-page list write.
On VAX systems, the MPW_WRTCLUSTER default value and maximum value is 120 512-byte pages; its minimum value is 16 512-byte pages.
On Alpha and I64 systems, the MPW_WRTCLUSTER default value is 64 8192-byte pages; its maximum value is 512 8192-byte pages; and its minimum value is 16 8192-byte pages.
On VAX systems, MSCP_BUFFER specifies the number of pages to be allocated to the MSCP server's local buffer area.
On Alpha and I64 systems, MSCP_BUFFER specifies the number of pagelets to be allocated to the MSCP server's local buffer area.
The MSCP_CMD_TMO default value of 0 is normally adequate. A value of 0 provides the same behavior as in previous releases of OpenVMS (which did not have an MSCP_CMD_TMO system parameter). A nonzero setting increases the amount of time before an MSCP command times out.
If command timeout errors are being logged on client nodes, setting the parameter to a nonzero value on OpenVMS servers reduces the number of errors logged. Increasing the value of this parameter reduces the numb client MSCP command timeouts and increases the time it takes to detect faulty devices.
If you need to decrease the number of command timeout errors, HP recommends that you set an initial value of 60. If timeout errors continue to be logged, you can increase this value in increments of 20 seconds.
The default value is currently 32. Unless a system has very constrained memory available, HP recommends that these values not be increased.
| Value | Description |
|---|---|
| 0 | Do not load the MSCP server. This is the default value. |
| 1 | Load the MSCP server and serve disks as specified by the MSCP_SERVE_ALL parameter. |
Starting with OpenVMS Version 7.2, the serving types are implemented as a bit mask. To specify the type of serving your system will perform, locate the type you want in the following table and specify its value. For some systems, you may want to specify two serving types, such as serving the system disk and serving locally attached disks. To specify such a combination, add the values of each type, and specify the sum.
In a mixed-version cluster that includes any systems running OpenVMS Version 7.1-x or earlier, serving all available disks is restricted to serving all disks except those whose allocation class does not match the system's node allocation class (prior to Version 7.2). To specify this type of serving, use the value 9 (which sets bit 0 and bit 3).
The following table describes the serving type controlled by each bit and its decimal value:
| Bit and Value When Set |
Description |
|---|---|
| Bit 0 (1) | Serve all available disks (locally attached and those connected to HS x and DSSI controllers). Disks with allocation classes that differ from the system's allocation class (set by the ALLOCLASS parameter) are also served if bit 3 is not set. |
| Bit 1 (2) | Serve locally attached (non-HS x and DSSI) disks. |
| Bit 2 (4) | Serve the system disk. This is the default setting. This setting is important when other nodes in the cluster rely on this system being able to serve its system disk. This setting prevents obscure contention problems that can occur when a system attempts to complete I/O to a remote system disk whose system has failed. |
| Bit 3 (8) |
Restrict the serving specified by bit 0. All disks except those with
allocation classes that differ from the system's allocation class (set
by the ALLOCLASS parameter) are served.
This is pre-Version 7.2 behavior. If your cluster includes systems running OpenVMS 7.1- x or earlier, and you want to serve all available disks, you must specify 9, the result of setting this bit and bit 0. |
Although the serving types are now implemented as a bit mask, the values of 0, 1, and 2, specified by bit 0 and bit 1, retain their original meanings:
0 --- Do not serve any disks (the default for earlier versions of OpenVMS).
1 --- Serve all available disks.
2 --- Serve only locally attached (non-HSx and non-DSSI) disks.
If the MSCP_LOAD system parameter is 0, MSCP_SERVE_ALL is ignored.
Specify one of the following values:
| Value | Description |
|---|---|
| 0 | Load the uniprocessing synchronization image SYSTEM_SYNCHRONIZATION_UNI.EXE. |
| 1 | If the CPU type is capable of SMP and two or more CPUs are present on the system, load the full-checking multiprocessing synchronization image SYSTEM_SYNCHRONIZATION.EXE. Otherwise, load the uniprocessing synchronization image SYSTEM_SYNCHRONIZATION_UNI.EXE. |
| 2 | Always load the full-checking version SYSTEM_SYNCHRONIZATION.EXE, regardless of system configuration or CPU availability. |
| 3 |
If the CPU type is capable of SMP and two or more CPUs are present on
the system, load the optimized streamlined multiprocessing image:
Otherwise, load the uniprocessing synchronization image SYSTEM_SYNCHRONIZATION_UNI.EXE. The default value is 3. |
| 4 | Always load the streamlined multiprocessing image SYSTEM_SYNCHRONIZATION_MIN.EXE, regardless of system configuration or CPU availability. |
Setting the SYSTEM_CHECK parameter to 1 has the effect of setting MULTIPROCESSING to 2.
| Value | Description |
|---|---|
| 0 | Both Thread Manager upcalls and the creation of multiple kernel threads are disabled. |
| 1 | Thread Manager upcalls are enabled; the creation of multiple kernel threads is disabled. |
| 2-256 (Alpha only) | Both Thread Manager upcalls and the creation of multiple kernel threads are enabled. The number specified represents the maximum number of kernel threads that can be created for a single process. |
The maximum value for MULTITHREAD is 256.
The system issues a mount verification message after a sequence of MVSUPMSG_NUM mount verifications have gone unannounced on a specific fibre channel disk device within a span of MVSUPMSG_INTVL seconds.
If this parameter is zero, all mount verification messages are announced.
The system issues a mount verification message after a sequence of MVSUPMSG_NUM mount verifications have gone unannounced on a specific fibre channel disk device within a span of MVSUPMSG_INTVL seconds.
If this parameter is zero, all mount verification messages are announced.
NISCS_MAX_PKTSZ allows the system manager to change the packet size used for cluster communications on network communication paths. PEDRIVER automatically allocates memory to support the largest packet size that is usable by any virtual circuit connected to the system up to the limit set by this parameter. Its default values are different for OpenVMS Alpha/I64 and OpenVMS VAX:
PEDRIVER uses NISCS_MAX_PKTSZ to compute the maximum amount of data to transmit in any LAN packet:
LAN packet size <= LAN header (padded Ethernet format)
+ NISCS_MAX_PKTSZ
+ NISCS checksum (only if data checking
is enabled)
+ LAN CRC or FCS
|
The actual packet size automatically used by PEDRIVER might be smaller than the NISCS_MAX_PKTSZ limit for any of the following reasons:
The actual memory allocation includes the required data structure overhead used by PEDRIVER and the LAN drivers, in addition to the actual LAN packet size.
The following table shows the minimum NISCS_MAX_PKTSZ value required to use the maximum packet size supported by specified LAN types:
| Type of LAN | Minimum Value for NISCS_MAX_PKTSZ |
|---|---|
| Ethernet | 1498 |
| FDDI | 4468 |
| Gigabit Ethernet | 8192 |
| ATM | 7606 |
Note that the maximum packet size for some Gigabit Ethernet adapters is larger than the maximum value of NISCS_MAX_PKTSZ (8192 bytes). See the LAN_FLAGS parameter for a description of how to enable jumbo frames on Gigabit Ethernet---that is, packet sizes larger than those noted for Ethernet.
Starting with OpenVMS Version 7.3-1, you can use the SCACP command SET VC/CHECKSUMMING to specify data checking on the VCs to certain nodes. You can do this on a running system. (Refer to the SCACP documentation in this manual for more information.)
Changing the setting of NISCS_PORT_SERV, on the other hand, requires a reboot. Furthermore, this parameter applies to all virtual circuits between the node on which it is set and other nodes in the cluster.
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.
This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.
HP sets the default value of NPAGECALC to 1 only during the initial boot after an installation or upgrade. When the value of NPAGECALC is 1, the system calculates an initial value for the NPAGEVIR and NPAGEDYN system parameters. This calculated value is based on the amount of physical memory in the system.
NPAGECALC's calculations do not reduce the values of NPAGEVIR and NPAGEDYN from the values you see or set at the SYSBOOT prompt. However, NPAGECALC's calculation might increase these values.
AUTOGEN sets NPAGECALC to 0. NPAGECALC should always remain 0 after AUTOGEN has determined more refined values for the NPAGEDYN and NPAGEVIR system parameters.
To set a value for this parameter, use AUTOGEN initially, and then monitor the amount of space actually used with the DCL command SHOW MEMORY/POOL/FULL.
For the benefit of OpenVMS VAX systems with limited physical memory, AUTOGEN logs a warning message in its report if NPAGEDYN exceeds 10 percent of physical memory or if NPAGEVIR exceeds 33 percent of physical memory.
AUTOGEN also limits its own calculated value for NPAGEDYN to 20 percent of physical memory and limits NPAGEVIR to 50 percent of physical memory. These calculated values are adequate for most workstations and systems with 16 or fewer megabytes of physical memory. If your system requires a larger value, you can override the AUTOGEN calculated values by setting higher values in MODPARAMS.DAT.
Also notice that the OpenVMS system might round the specified values higher to an even number of pages for each RAD, which prevents the base RAD from having too little nonpaged pool. For example, if the hardware is an AlphaServer GS160 with 4 RADs:
NPAGEDYN = 6291456 bytes NPAGERAD = 2097152 bytes |
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