vxiod(1M)                        VxVM 3.5                         vxiod(1M)
                                 1 Jun 2002



 NAME    [Toc]    [Back]
      vxiod - start, stop, and report on VERITAS Volume Manager kernel
      daemons

 SYNOPSIS    [Toc]    [Back]
      vxiod

      vxiod [-f ] [set count]

 DESCRIPTION    [Toc]    [Back]
      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
      volume 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    [Toc]    [Back]
      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
                created, the requested number is silently truncated to that
                maximum.

 OPTIONS    [Toc]    [Back]
      -f        Forcibly kills the last I/O daemon.  Without this option,
                the number of I/O daemons cannot be reduced to zero.

 EXIT CODES    [Toc]    [Back]
      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.




                                    - 1 -       Formatted:  January 24, 2005






 vxiod(1M)                        VxVM 3.5                         vxiod(1M)
                                 1 Jun 2002



 FILES    [Toc]    [Back]
      /dev/vx/iod                   The device used to report on and start
                                    volume I/O daemon processes.

 NOTES    [Toc]    [Back]
      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 produced by the ps command.

 SEE ALSO    [Toc]    [Back]
      ps(1), vxconfigd(1M), vxdctl(1M), vxintro(1M), fork(2), vxio(7),
      vxiod(7)


                                    - 2 -       Formatted:  January 24, 2005