System Management Release Notes
4.9 PAGED_LAL_SIZE New System Parameter
4.9 PAGED_LAL_SIZE New System Parameter
PAGED_LAL_SIZE sets the maximum size, in bytes, to use the page dynamic
pool lookaside lists.
4.9.1 Paged Pool Lookaside Lists
V8.4
Paged dynamic pool now allows the use of lookaside lists to increase system
performance in some cases. It is controlled by SYSGEN parameter PAGED_LAL_
SIZE and is off (0) by default.
If the variable paged pool freelist becomes fragmented, you might benefitby
enabling the use of these lookaside lists. The SYSGEN parameter PAGED_LAL_
SIZE sets the maximum size, in bytes, to use for these lookaside lists. Packets
larger than this size will still be allocated from the variable paged pool freelist. A
modest value, 512 bytes, has been found to help systems doing intensive logical
name creation and deletion operations.
Since the parameter is dynamic it can be enabled, adjusted, or disabled as
needed. If it was enabled and then lowered there might be some packets on
the paged pool lookaside lists that are no longer actively in use. These show up
as "Over-limit Lookaside Blocks" in DCL’s and SDA’s
SHOW MEMORY/POOL/FULL
command. These packets were used before but are now larger than the new
PAGED_LAL_SIZE. These packets will be used again if the SYSGEN parameter
is increased to include them, or if there is a paged pool shortage and the packets
are reclaimed from the lookaside lists.
To help prevent a runaway condition where packets on a lookaside list starts to
consume most or all of paged pool, the paged pool lookaside lists will not be used
for packets in the last quarter of paged dynamic pool. If there is a paged pool
memory shortage packets on the lookaside lists will be reclaimed as well.
If disabled, at the default value of 0, paged pool behaves as it did in previous
versions of OpenVMS, allocating and deallocating packets from the paged pool
variable freelist.
4.10 2 TiB Disk Volume Support Restrictions
V8.4
OpenVMS Version 8.4 supports disk volumes up to 2 TiB in size with the
following restrictions:
• With OpenVMS versions prior to version 8.4, there is no support for volumes
larger than 1 TiB in size or for mounting of volumes larger than 1 TiB. To
prevent accidental mounts on earlier versions of OpenVMS, the latest patches
for MOUNT will explicitly disallow mounting of volumes larger than 1 TiB on
such systems.
• The lexical function F$GETDVI() with items codes MAXBLOCK,
FREEBLOCKS, EXPSIZE, and VOLSIZE will return a negative number
if the value is larger than 1 TiB. This is due to the fact that DCL does 32-bit
signed integer arithmetic and comparisons. Command procedures that use
F$GETDVI( ) with these item codes may need to be modified to work with
volumes larger than 1 TiB. For more information about handling numeric
values outside the range of DCL integer representation using DCL, see the
HP OpenVMS DCL Dictionary.
System Management Release Notes 4–11
