HP OpenVMS System Management Utilities Reference Manual

The maximum value for MULTITHREAD is 256.

MVSUPMSG_INTVL (D)

(Alpha and I64) The system suppresses mount verification start and end messages for fibre channel disk devices if mount verification completes on the first attempt and if mount verification does not occur too often. MVSUPMSG_NUM and this parameter establish this limit.

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.

MVSUPMSG_NUM (D)

If this parameter is zero, all mount verification messages are announced.

MVTIMEOUT (A on Alpha and I64,D)

MVTIMEOUT is the time in seconds that a mount verification attempt continues on a given disk volume. If the mount verification does not recover the volume within that time, the I/O operations outstanding to the volume terminate abnormally.

NET_CALLOUTS (D)

NET_CALLOUTS is normally set to 0. A value of 255 indicates that no attempt is to be made to assign a new proxy connection to an active server, but that a new process must be started to invoke the installation security policy callout modules in LOGINOUT.EXE. Values 1 through 254 are reserved for future use.

NISCS_CONV_BOOT

NISCS_CONV_BOOT controls whether a conversational boot is permitted during a remote system boot. The default value of 0 specifies that conversational boots are not permitted.

NISCS_LOAD_PEA0

NISCS_LOAD_PEA0 controls whether the NI-SCS port driver PEDRIVER is loaded during system boot. The default of 0 specifies that the PEDRIVER is not loaded.

NISCS_MAX_PKTSZ (A on Alpha and I64)

This parameter specifies an upper limit on the size, in bytes, of the user data area in the largest packet sent by NISCA on any local area network (LAN).

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:

On Alpha and I64, to optimize performance, the default value is the largest packet size currently supported by OpenVMS.
On VAX, to conserve memory, the default value is the Ethernet packet size.

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:

On a per-LAN path basis, if PEdriver determines that the LAN path between two nodes, including the local and remote LAN adapters and intervening LAN equipment, can only convey a lesser size.
In other words, only nodes with large-packet LAN adapters connected end-to-end by large-packet LAN equipment can use large packets. Nodes connected to large-packet LANs but having an end-to-end path that involves an Ethernet segment restrict packet size to that of an Ethernet packet (1498 bytes).
For performance reasons, PEDRIVER might further limit the upper bound on packet size so that the packets can be allocated from a lookaside list in the nonpaged pool.

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 4382 (before Version 7.3)
4396 (Version 7.3 and later)

Gigabit Ethernet 8192

ATM 7606

Type of LAN	Minimum Value for NISCS_MAX_PKTSZ
Ethernet	1498
FDDI	4382 (before Version 7.3) 4396 (Version 7.3 and later)
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.

NISCS_PORT_SERV (A, D)

NISCS_PORT_SERV provides flag bits for PEDRIVER port services:

Setting bits 0 and 1 (decimal value 3) enables data checking.
Setting bit 4 enables data compression on all virtual channels (VCs) to nodes that support compression.

The remaining bits are reserved for future use.

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. (For more information, see the SCACP documentation in this manual.

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.

NOAUTOCONFIG (D)

NOAUTOCONFIG controls whether all devices are automatically configured when the system boots. The default value of 0 sets the system to automatically configure all devices. Set NOAUTOCONFIG to 1 (no automatic configuration) only for debugging purposes.

This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.

NOCLUSTER

NOCLUSTER controls whether page read clustering is inhibited when the system boots. Set NOCLUSTER to 1 (inhibit page read clustering) only for debugging purposes.

This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.

NOPGFLSWP

If enabled, NOPGFLSWP disables swapping into page files.

This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.

NPAGECALC

NPAGECALC controls whether the system automatically calculates the initial size for nonpaged dynamic memory.

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.

NPAGEDYN (A,F,G,M)

NPAGEDYN sets the size of the nonpaged dynamic pool in bytes. This figure is rounded down to an integral number of pages. NPAGEDYN establishes the initial setting of the nonpaged pool size, but the pool size can be increased dynamically.

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.

NPAGERAD (G)

(Alpha and I64) NPAGERAD specifies the total number of bytes of nonpaged pool that will be allocated for Resource Affinity Domains (RADs) other than the base RAD. For platforms that have no RADs, NPAGERAD is ignored. Notice that NPAGEDYN specifies the total amount of nonpaged pool for all RADs.

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

In this case, the OpenVMS system allocates a total of approximately 6,291,456 bytes of nonpaged pool. Of this amount, the system divides 2,097,152 bytes among the RADs that are not the base RAD. The system then assigns the remaining 4,194,304 bytes to the base RAD.

Note

The system actually rounds up to an even number of pages on each RAD. In addition, the base RAD is never assigned a value less than the smaller of the value of NPAGEDYN and 4 megabytes.

On AlphaServer GS series processors on OpenVMS systems prior to Version 7.3-1, system managers frequently saw pool expansion that increasing NPAGEDYN did not reduce. This problem was caused by leaving NPAGERAD at its default value of 0.

Starting with OpenVMS Version 7.3-1, when NPAGERAD is 0 (the default), the system calculates a value to use for NPAGERAD with the following formula:

Base RAD memory NPAGEDYN * (1- --------------- ) Total memory

This calculation gives more pool to the non-base RADs than before and, therefore, reduces the expansion of non-base RADs.

NPAGEVIR (A, G)

NPAGEVIR defines the maximum size to which NPAGEDYN can be increased. If this value is too small, the system can hang. If NPAGEVIR is too large, the result is a penalty of 4 bytes per extra page on VAX and 8 bytes per extra page on Alpha and I64.

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.

NPAG_AGGRESSIVE (D)

Beginning with OpenVMS Version 8.2, the default values of NPAG_AGGRESSIVE and NPAG_GENTLE are 100. A value of 100 turns off both gentle and aggressive reclamation of nonpaged pool lookaside lists. In many cases, when pool reclamation moves small packets from the lookaside lists back to the variable list, the result is fragmentation of the variable list. This fragmentation appears as many small packets at the front of the variable list and a few large packets at the end of the list.

When an allocation occurs for a packet that is larger than any of the lookaside lists, the system must find a large enough packet on the variable list. When heavily fragmented, the entire variable list often must be searched to find a large enough packet. Because the variable list is kept in address order, when a large packet is deallocated, the entire list must be searched again to deallocate the packet.

Under these conditions, system performance can be severely degraded. For this reason, HP recommends that you turn off pool reclamation but keep both NPAG_AGGRESSIVE and NPAG_GENTLE system parameters set to 100.

NPAG_BAP_MAX

(Alpha and I64) NPAG_BAP_MAX is the size in bytes of the bus addressable pool (BAP) that the system creates under normal circumstances.

NPAG_BAP_MAX_PA

(Alpha and I64) NPAG_BAP_MAX_PA is the highest physical address in megabytes that is allowed in bus addressable pool (BAP).

NPAG_BAP_MIN

(Alpha and I64) NPAG_BAP_MIN is the size in bytes of the bus addressable pool (BAP) that the system creates when memory resources are unusually constrained.

NPAG_BAP_MIN_PA

(Alpha and I64) NPAG_BAP_MIN_PA specifies the lowest physical address in megabytes that is allowed in bus addressable pool (BAP).

NPAG_GENTLE (D)

Beginning with Version 8.2, the default values of NPAG_AGGRESSIVE and NPAG_GENTLE are 100. A value of 100 turns off both gentle and aggressive reclamation of nonpaged pool lookaside lists. In many cases, when pool reclamation moves small packets from the lookaside lists back to the variable list, the result is fragmentation of the variable list. This fragmentation appears as many small packets at the front of the variable list and a few large packets at the end of the list.

NPAG_INTERVAL (D)

NPAG_INTERVAL is the number of seconds between passes of nonpaged-pool gentle reclamation.

NPAG_RING_SIZE

NPAG_RING_SIZE represents the number of entries in the ring buffer.

PAGEDYN (A,F,G,M)

PAGEDYN sets the size of the paged dynamic pool in bytes. The specified value is rounded down to an integral number of pages. Each page of paged dynamic pool adds 8 bytes of permanently resident memory to the system page table; the paged dynamic pool has no other direct memory requirements.

The paged dynamic pool is used to allocate storage for shared logical names, resident image headers, known file list entries, and RMS file-sharing structures. Substantial amounts of space for the pool can be overallocated with little effect on system performance.

The size of the paged pool can grow dynamically up to the maximum size that this parameter specifies.

PAGFILCNT (G)

On VAX systems, PAGFILCNT defines the maximum number of page files that can be installed.

On Alpha and I64 systems, beginning in OpenVMS Version 7.3, this parameter is obsolete.

PAGTBLPFC

PAGTBLPFC specifies (in pages) the maximum number of page tables to read to satisfy a fault for a nonresident page table.

This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.

PAMAXPORT (D)

PAMAXPORT specifies the maximum port number to be polled on each CI and DSSI. The CI and DSSI port drivers poll to discover newly initialized ports or the absence/failure of previously responding remote ports.

A system does not detect the existence of ports whose port numbers are higher than this parameter's value. Thus, set this parameter to a value that is equal to or greater than the highest port number being used on any CI or DSSI connected to the system.

You can decrease this parameter to reduce polling activity if the hardware configuration has fewer than 16 ports. For example, if the CI or DSSI with the largest configuration has a total of 5 ports assigned to port numbers 0 through 4, you could set PAMAXPORT to 4.

If CI or DSSI devices are not configured on your system, this parameter is ignored.

The default for this parameter is 15 (poll for all possible ports 0 through 15). HP recommends that you set this parameter to the same value on each cluster computer.

PANOPOLL (D)

Disables CI and DSSI polling for ports if set to 1. (The default is 0.) When PANOPOLL is set, a computer does not discover that another computer has shut down or powered down promptly and does not discover a new computer that has booted. This parameter is useful when you want to bring up a computer detached from the rest of the cluster for checkout purposes.

PANOPOLL is functionally equivalent to uncabling the system from the DSSI or star coupler. This parameter does not affect OpenVMS Cluster communications by LAN.

The default value of 0 is the normal setting and is required if you are booting from an HSC controller or if your system is joining an OpenVMS Cluster. This parameter is ignored if no CI or DSSI devices are configured on your system.

PANUMPOLL (D)

PANUMPOLL establishes the number of CI and DSSI ports to be polled each polling interval. The normal setting for PANUMPOLL is 16.

On systems with less powerful CPUs, the parameter may be useful in applications sensitive to the amount of contiguous time that the system spends at IPL 8. Reducing PANUMPOLL reduces the amount of time spent at IPL 8 during each polling interval, while increasing the number of polling intervals needed to discover new or failed ports.

If CI or DSSI devices are not configured on your system, this parameter is ignored.

PAPOLLINTERVAL (D)

Specifies, in seconds, the polling interval the CI port driver uses to poll for a newly booted computer, a broken port-to-port virtual circuit, or a failed remote computer.

This parameter trades polling overhead against quick response to virtual circuit failures. HP recommends that you use the default value for this parameter.

HP recommends that you set this parameter to the same value on each cluster computer.

PAPOOLINTERVAL (D)

Specifies, in seconds, the interval at which the port driver checks available nonpaged pool after a pool allocation failure.

This parameter trades faster response to pool allocation failures against increased polling overhead. HP recommends that you use the default value for this parameter.

If CI or DSSI devices are not configured on your system, this parameter is ignored.

PASANITY (D)

PASANITY controls whether the CI and DSSI port sanity timers are enabled to permit remote systems to detect a system that has been hung at IPL 8 or above for 100 seconds. It also controls whether virtual circuit checking gets enabled on the local system. The TIMVCFAIL parameter controls the time (1-99 seconds).

PASANITY is normally set to 1 and should be set to 0 only when you are debugging with XDELTA or planning to halt the CPU for periods of 100 seconds or more.

PASANITY is only semidynamic. A new value of PASANITY takes effect on the next CI or DSSI port reinitialization.

If CI or DSSI devices are not configured on your system, this parameter is ignored.

PASTDGBUF (A)

The number of datagram receive buffers to queue initially for the cluster port driver's configuration poller. The initial value is expanded during system operation, if needed.

Memory Channel devices ignore this parameter.

PASTIMOUT (D)

The basic interval at which the CI port driver wakes up to perform time-based bookkeeping operations. It is also the period after which a timeout is declared if no response to a start handshake datagram has been received.

If CI or DSSI devices are not configured on your system, this parameter is ignored.

The default value should always be adequate.

PE*

PE1, PE2, PE3, PE4, PE5, PE6 are reserved for HP use only. These parameters are for cluster algorithms and their usages can change from release to release. HP recommends using the default values for these special parameters.

PFCDEFAULT (A,D)

On VAX systems during execution of programs, PFCDEFAULT controls the number of image pages read from disk per I/O operation when a page fault occurs. The PFCDEFAULT maximum default value is 127 512-byte pages.

On Alpha and I64 systems during execution of programs, PFCDEFAULT controls the number of image pagelets read from disk per I/O operation when a page fault occurs. The PFCDEFAULT maximum default value is 2032 512-byte pagelets (127 8192-byte Alpha and I64 pages).

The read I/O operations can take place from an image file or from the page file. The actual size of the cluster can be less than PFCDEFAULT, depending on the size of image sections and the pattern of page references.

The value should not be greater than one-fourth the default size of the average working set to prevent a single page fault from displacing a major portion of a working set. Too large a value for PFCDEFAULT can hurt system performance. PFCDEFAULT can be overridden on an image-by-image basis with the CLUSTER option of the OpenVMS linker.

PFN_COLOR_COUNT

(Alpha and I64) PFN_COLOR_COUNT specifies the number of buckets (colors) into which all members of the zeroed page list and all unencumbered members of the free page list are sorted. OpenVMS Alpha systems might derive a preferred page color from a request to map a given virtual page and attempt to map that virtual page to a PFN of matching "color." This results in less variance in which cache blocks are used when accessing that page. This might or might not improve performance, depending on the application.

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 you increase this parameter, you must also increase the ZERO_LIST_HI system parameter.

PFRATH (A on Alpha and I64,D,M)

PFRATH specifies the page fault rate above which the limit of a working set is automatically increased. The unit of measure is the number of faults per 10 seconds of processor time. At a setting of 120, for example, the system automatically increases the limit of a working set if it is faulting more than 120 pages per 10 seconds. Decreasing the value of this parameter tends to increase the limits of the working sets, while increasing its value tends to decrease their limits.

On VAX systems, the default value is 120 page faults every 10 seconds.

On Alpha and I64 systems, the default value is 8 page faults every 10 seconds.

PFRATL (A,D,M)

PFRATL specifies the page fault rate below which the limit of a working set is automatically decreased. The unit of measure is the number of faults per 10 seconds of processor time. At a setting of 1, for example, the system automatically decreases the limit of a working set if it is faulting less than 1 page every 10 seconds.

Increasing the value of this parameter tends to decrease the limits of the working sets, while decreasing its value tends to increase their limits.

PHYSICAL_MEMORY (A)

(Alpha and I64) PHYSICAL_MEMORY specifies the amount of physical memory available for use. The default setting is --1, which equates to all memory in the system. Decreasing this parameter allows you to test smaller configurations of memory without having to remove memory boards.

This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.

Because of hardware configuration requirements on the AlphaServer ES47/ES80/GS1280 systems, HP does not recommend altering the setting of the system parameter PHYSICAL_MEMORY from its default setting of -1. Artificially reducing the amount of memory can produce unpredictable results on these systems.

PHYSICALPAGES (A)

(VAX only) PHYSICALPAGES sets the maximum number of physical pages of memory to be used on the system. Decreasing this parameter allows you to test smaller configurations of memory without the need to remove memory boards.

This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.

PIOPAGES (A,D)

PIOPAGES specifies the size of the process I/O segment, which holds data structures and buffer pool space for RMS to use when it handles I/O that involves process-permanent files. Once PIOPAGES is reset in SYSGEN, any new process receives the changed value.

Beginning with OpenVMS Version 7.2, the default value has been raised to 575. The setting has been raised to accommodate the increased demands for process-permanent memory that result from changes made to RMS file-naming parsing in Version 7.2.

This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.

PIXSCAN (A,D)

PIXSCAN specifies the number of process index slots scanned each second for computable or computable-outswapped processes. These processes receive an automatic priority boost for 1 quantum, unless the priority of the currently executing process is greater than 15. The priority boost is done to avoid potential deadlocks on the system.

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 (D)

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).

POOLPAGING

POOLPAGING enables (1) paging of pageable dynamic pool.

This special parameter is used by HP and is subject to change. Do not change this parameter unless HP recommends that you do so.

POWEROFF (D)

POWEROFF enables or disables software requests to the console firmware to remove power from the system. This parameter should normally be turned ON (1) to allow software to make power-off requests. However, POWEROFF can be set to OFF (0) to disable software power-off requests.

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