NAME
krsd — kernel registry services daemon
SYNOPSIS
krsd
-1
krsd
[-i]
[-d
seconds]
DESCRIPTION
krsd
saves data, flagged as persistent in the core kernel KRS tree, to files on disk.
These files are read when the system is booted, in order to restore the
aforementioned persistent data.
When running in daemon mode,
krsd
sleeps,
waking periodically to check if any persistent data has changed since the
last save.
If persistent data has changed, the new state of the data is saved to disk.
Otherwise,
krsd
sleeps for another period of time and then repeats the process.
When running in
one time
(non-daemon) mode,
krsd
unconditionally saves persistent data to disk and then exits.
Normally,
krsd
is executed in daemon mode by
init(1M).
The
/etc/inittab
entry for
krsd
will cause
krsd
to be respawned automatically if it is terminated.
krsd
uses the
syslog
message logging facility to log all
krsd
activity.
Persistent KRS data is maintained in files based on the
class
of the data in question.
Currently, the following
classes
are recognized:
- system specific
Data that applies to the system in general,
regardless of what kernel is booted.
This data is saved in the file:
system.krs.
- kernel specific
Data specific to a given bootable kernel.
This data is saved in the file:
kernel_name.krs.
Where
kernel_name
is the full path name of the kernel in question,
with slashes replaced by underscores.
NOTE: This naming scheme is subject to change in the future.
These files are maintained in the following directories:
- /stand/krs
The primary KRS directory. This is the directory from which
the files are loaded when the system is booted.
It contains the most recent, consistent copy of persistent
KRS data.
- /stand/krs_lkg
This directory contains the
last known good
copies of the KRS data.
The files in
/stand/krs
are copied to this directory when the system
successfully reaches the
sysinit
init state.
They are loaded, during boot, if the files in
/stand/krs
are missing or corrupt.
This scheme ensures that the system will be able to
boot to
sysinit,
in the event the primary KRS files are found to be corrupt.
Once the
sysinit
state is reached,
more recent versions of the KRS data can be restored to
/stand/krs
and the system rebooted.
- /stand/krs_tmp
This directory contains temporary copies of the KRS data files.
Data is first saved to files in this directory.
Once the save is complete, the files are linked to
/stand/krs
and unlinked from
/stand/krs_tmp.
Options
krsd
recognizes the following options:
- -1
One time
mode, unconditionally save persistent data to disk, then exit.
- -i
Run from
inittab,
parent does not spawn a child nor exit.
Required if
respawn
from inittab is to work properly.
- -d seconds
Set the delay time to
seconds
seconds.
This is the time interval between attempted saves of persistent data.
The default interval is 300 seconds.
AUTHOR
krsd
was developed by Hewlett-Packard Company.
FILES
- /stand/krs/*
Primary KRS files
- /stand/krs_lkg/*
Last known good KRS files.
- /stand/krs_tmp/*
Temporary KRS files.
- /dev/devkrs
Pseudo driver.
SEE ALSO
krs_flush(1M),
krs(5).
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