*** UNIX MANUAL PAGE BROWSER ***

voliod(8) System Manager's Manual voliod(8) NAME voliod - Start, stop, and report on Logical Storage Manager (LSM) ker- nel daemons SYNOPSIS /sbin/voliod set count /sbin/voliod logio volume_major/volume_minor|volume_path ... /sbin/voliod stoplogio -e volume_major/volume_minor|volume_path ... DESCRIPTION The voliod utility starts, stops, or reports on Logical Storage Manager error daemons and volume log I/O daemons. An error daemon is a process that the volume driver uses for extended error-recovery and plex-recov- ery operations. At least one error daemon is required by the volume driver to process these recovery operations, with each error daemon se- rially processing one error operation at a time. A volume log I/O dae- mon is used by the Logical Storage Manager driver to schedule writes for volumes that require logging. OPERATION When invoked with no arguments, /sbin/voliod prints the current number of volume error daemons on the standard output. When invoked with the set keyword, the number of daemons specified by count will be created. If more volume error daemons exist than are specified by count, then the excess processes will be terminated. If more than the maximum number are created (currently 20), the requested number will be silently truncated to that maximum. The number of daemons to create for general I/O handling is dependent on system load and usage. The daemons are only used in the event of volume recoveries or errors. It is generally not necessary to start more than one daemon for each CPU on the system. If volume recovery seems to proceed slower at some times, then it may be worthwhile to create more daemons. Each error daemon starts in the background and creates an asynchro- nously-running process, which detaches itself from the controlling ter- minal and becomes a volume error daemon. The voliod utility does not wait for these processes to complete. Logging daemons are created and killed automatically by vold, but if they are not available for some reason, then they can be started manu- ally using the following procedure. When invoked with the keyword logio, voliod creates a volume log I/O daemon for the volume device or major/minor number pair specified in the operand list. If specified as a device path, the path should point to the block device file for the volume. This is usually specified as /dev/vol/... If specified as a major/minor number pair, the major num- ber should relate to the block device major number of the Logical Stor- age Manager and the minor number to the minor number of the volume. The log I/O daemon is started in the foreground and will only return if it is killed using the stoplogio option to voliod. When invoked with the keyword stoplogio, voliod kills any logging daemons associated with the specified volume device or major/minor number pair. OPTIONS The following options are used by voliod: Do not print error messages that may be generated as a result of starting a logio daemon twice on the same volume. Force the kill of the last error daemon. Without this option, the error daemons can only be reduced to one. EXIT CODES The voliod utility prints a diagnostic on the standard error, and exits if an error is encountered. If an error occurs within a forked error daemon process, then the error is not reflected in the exit status for voliod. Otherwise, voliod returns a nonzero 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 re- ported. If any other error occurs, the exit status is 3. FILES /dev/voliod The device used to report on and start volume I/O daemon processes. CAVEATS If a /sbin/voliod logio command is issued in the foreground from the command line, then the only way to release the session is to stop the daemon using the /sbin/voliod stoplogio command. NOTE Volume log I/O daemons are created automatically by vold when they are needed, and are killed automatically when they are no longer needed. Log I/O daemons cannot be killed directly through the use of signals. RELATED INFORMATION fork(2), volintro(8), vold(8), voldctl(8) delim off voliod(8)