vxiod

NAME

vxiod - start, stop, and report on VERITAS Volume Manager kernel daemons

SYNOPSIS

DESCRIPTION

The vxiod utility starts, stops, or reports on VERITAS Volume Manager (VxVM) I/O daemons. An I/O daemon provides a process context for performing I/O in VxVM. VERITAS Volume Manager I/O daemons are not required for correct operation, but not having I/O daemons can adversely affect system performance.

When invoked with no arguments, vxiod prints the current number of I/O daemons on the standard output.

The number of daemons to create for general I/O handling is dependent on system load and usage. If volume recovery seems to proceed slower at times, it may be worthwhile to create more daemons.

Each I/O daemon starts in the background and creates an asynchronously-running process, which detaches itself from the controlling terminal and becomes a volume I/O daemon. The vxiod utility does not wait for these processes to complete.

KEYWORDS

set

When invoked with the set keyword, vxiod creates the number of daemons specified by count. If more volume I/O daemons exist than are specified by count, the excess processes terminate. If more than the maximum number (64) are specified, the requested number is silently truncated to that maximum.

OPTIONS

-f

Forcibly kills the last I/O daemon. Without this option, the number of I/O daemons cannot be reduced to zero.

EXIT CODES

The vxiod utility prints a diagnostic on the standard error, and exits if an error is encountered. If an I/O occurs within a forked I/O daemon process, then the I/O is not reflected in the exit status for vxiod. Otherwise, vxiod returns a non-zero exit status on errors.

Usage errors result in an exit status of 1 and a usage message. If the requested number of daemons cannot be created, then the exit status is 2, and the number of daemons that were successfully started is reported. If any other error occurs, the exit status is 3.

FILES

/dev/vx/iod

The device used to report on and start volume I/O daemon processes.

NOTES

VERITAS Volume Manager I/O daemons cannot be killed directly through the use of signals.

The number of VERITAS Volume Manager I/O daemons currently running can only be determined by running vxiod; I/O daemons do not appear in the list of processes output by the ps command.

SEE ALSO

fork(2), ps(1), vxconfigd (1M), vxdctl (1M), vxintro (1M), vxio (7), vxiod (7)