HP Process Resource Manager User's Guide

Glossary
disk group
Glossary292
disk group A single logical disk device
under control of VERITAS Volume Manager
(VxVM) formed from one or more physical
disk drives. PRM manages disk bandwidth
on a disk group basis as well as a logical
volume group basis.
disk manager A kernel routine that
monitors bandwidth at the level of logical
volume groups (LVM) and disk groups
(VxVM), rearranging I/O requests as needed
to ensure disk bandwidth shares.
disk bandwidth record (Also known as
“disk record.”) Record in a PRM
configuration file that specifies a group’s disk
bandwidth shares for a given logical volume
group or disk group.
effective user ID A form of user ID that
can allow users access to files they do not
own.
entitlement The minimum percentage
(lower limit) of CPU, memory, or disk
bandwidth resources guaranteed to a
particular PRM group when the total system
use of these resources is at 100%.
file ID ID used by the application manager
to place processes in the appropriate PRM
groups. The file ID is based on the file
system device and inode number.
group/CPU record Record in a PRM
configuration file that specifies a PRM
group’s name and its CPU allocation. PRM
requires two groups: PRM_SYS (PRMID 0) for
system processes and OTHERS (PRMID 1) for
users without user records. PRM
automatically creates the PRM_SYS group.
hierarchy An FSS PRM group hierarchy is
a nesting of groups. You specify resource
shares at each level of the hierarchy. If a
group has child groups, the parent group’s
resource shares are distributed to the
children based on the shares they are
assigned. If a group has no child groups, it
uses the shares itself.
HP-UX real-time process A process that
uses the HP-UX real-time scheduler
(rtprio). This type of process keeps its
assigned priorities because timely
scheduling is crucial to the operation of a
real-time process. Hence, a real-time process
is permitted to exceed its group’s CPU share
and max.
initial group The first PRM group listed in
a user record in a configuration file.
Typically, the applications a user launches
run in the user’s initial group—assuming
those applications do not have their own
application records. This is the group
prmconfig, prmmove -i, login, at, and
cron use to determine where to place user
processes. If a user does not have a user
record or is not in a netgroup that has a user
record, the user default group OTHERS
becomes the user’s initial group.
leaf group Any PRM group that has no
children (child groups). In a configuration
that does not use group hierarchies, all the
groups are leaf groups.
lockable memory Memory that can be
locked (that is, its pages kept in real memory
for the lifetime of a process) by the kernel, by
mlock(),orbyplock() is known as lockable
memory. Locked memory cannot be paged or
swapped out.