voliod(8)voliod(8)NAMEvoliod - Starts, stops, and reports on Logical Storage Manager kernel
I/O daemons
SYNOPSIS
/sbin/voliod
/sbin/voliod [-f] set count
OPTIONS
Force the kill of the last I/O daemon. Without this option, the I/O
daemons can only be reduced to one. See NOTES for an exception.
KEYWORDS
Sets the number of daemons to count.
DESCRIPTION
The voliod utility starts, stops, or reports on Logical Storage Manager
kernel I/O daemons. When invoked with no arguments, voliod prints the
current number of volume I/O daemons on the standard output. When
invoked with the set keyword, creates the number of daemons specified
by count. If more volume I/O daemons exist than are specified by count,
then the excess daemons will be terminated. If more than the maximum
number (64) are specified, the specified number will be silently lim‐
ited to that maximum.
The number of daemons necessary for general I/O handling depends on
system load and usage. One daemon for each CPU on the system (or a min‐
imum of two) is generally adequate, unless volume recovery seems unusu‐
ally slow.
Each I/O daemon starts in the background, creates an asynchronously
running kernel thread, and becomes a volume I/O daemon. The voliod
utility does not wait for these threads to complete.
NOTES
Logical Storage Manager (LSM) automatically sets the number of I/O dae‐
mons when the system starts, so it is usually not necessary to set or
change the number of I/O daemons with this command.
On systems where the system attribute Max_LSM_IO_PERFORMANCE is set to
1 (default is 0), the force option will not allow you to kill the last
daemon. You can reduce the number of daemons to 1 but not 0. Attempts
to kill the last daemon will result in an error message like the fol‐
lowing, and will leave the number of daemons unchanged: # voliod-f set
0 lsm:voliod: ERROR: VOL_IO_DAEMON_SET failed: Permission denied
See sys_attrs_lsm(5) for more information.
LSM I/O daemons cannot be stopped directly through the use of signals.
The number of Logical Storage Manager I/O daemons currently running can
be determined only by running voliod; I/O daemons do not appear in the
list of processes produced by the ps(1) command.
EXIT CODES
The voliod utility displays a diagnostic on the standard error and
exits if an error is encountered. If an I/O error occurs within a
spawned I/O daemon thread, then the I/O is not reflected in the exit
status for voliod. Otherwise, voliod returns a nonzero exit status on
errors, as follows: Usage errors. voliod displays a usage message.
The requested number of daemons cannot be started, and voliod reports
the number that were successfully started. All other errors.
FILES
The device used to start and report on volume I/O daemon kernel
threads.
SEE ALSO
Commands: vold(8), voldctl(8)
Functions: fork(2), pthread(3)
Other: sys_attrs_lsm(5), volintro(8)voliod(8)
