vxiod(1M)																 vxiod(1M)

NAME

       vxiod - start, stop, and report on Veritas Volume Manager I/O threads

SYNOPSIS

       vxiod

       vxiod [-f ] [set count]

DESCRIPTION

       The  vxiod utility starts, stops, or reports on Veritas Volume Manager (VxVM) I/O kernel threads.  An I/O thread provides a process context
       for performing I/O in VxVM.

       When the vxio module is loaded, 16 I/O threads are created, plus 2 threads per additional CPU for a system with more than 8 CPUs, up  to  a
       maximum	of  64	threads.  At least one I/O thread must be running while the vxio module is loaded, and the number of I/O threads cannot be
       forced to zero.

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

       The number of threads that is required for handling I/O requests depends on the system load and usage.  If volume recovery seems to proceed
       more slowly at times, it may be possible to improve its performance by increasing the number of I/O threads up to a maximum of 64.

KEYWORDS

       set	 When  invoked with the set keyword, vxiod creates the number of I/O threads specified by count.  If more volume I/O threads 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	 This option has no effect from release 5.0 onward.  The number of I/O threads 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 request occurs within a I/O
       thread, the state of that I/O request is not reflected in the exit status for vxiod.  Otherwise, vxiod returns a non-zero  exit	status	on
       error.

       Usage  errors  result in an exit status of 1 and a usage message.  If the requested number of threads cannot be created, the exit status is
       2, and the number of threads 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 threads.

NOTES

       Veritas Volume Manager I/O threads cannot be killed directly through the use of signals.

       Depending on the operating system, VxVM I/O threads may not appear in the list of processes that is output by the ps command.   The  number
       of I/O threads that is currently running can be determined by running vxiod.

SEE ALSO

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

VxVM 5.0.31.1							    24 Mar 2008 							 vxiod(1M)