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GRAID3(8)               FreeBSD System Manager's Manual              GRAID3(8)

     graid3 - control utility for RAID3 devices

     graid3 label [-hnrvw] name prov prov prov ...
     graid3 clear [-v] prov ...
     graid3 configure [-adhnrRvwW] name
     graid3 rebuild [-v] name prov
     graid3 insert [-hv] -n number name prov
     graid3 remove [-v] -n number name
     graid3 stop [-fv] name ...
     graid3 list
     graid3 status
     graid3 load
     graid3 unload

     The graid3 utility is used for RAID3 array configuration.  After a device
     is created, all components are detected and configured automatically.
     All operations such as failure detection, stale component detection,
     rebuild of stale components, etc. are also done automatically.  The
     graid3 utility uses on-disk metadata (the provider's last sector) to
     store all needed information.

     The first argument to graid3 indicates an action to be performed:

     label          Create a RAID3 device.  The last given component will
                    contain parity data, whilst the others will all contain
                    regular data.  The number of components must be equal to
                    3, 5, 9, 17, etc. (2^n + 1).

                    Additional options include:

                    -h     Hardcode providers' names in metadata.

                    -n     Turn off autosynchronization of stale components.

                    -r     Use parity component for reading in round-robin
                           fashion.  Without this option the parity component
                           is not used at all for reading operations when the
                           device is in a complete state.  With this option
                           specified random I/O read operations are even 40%
                           faster, but sequential reads are slower.  One
                           cannot use this option if the -w option is also

                    -w     Use verify reading feature.  When reading from a
                           device in a complete state, also read data from the
                           parity component and verify the data by comparing
                           XORed regular data with parity data.  If
                           verification fails, an EIO error is returned and
                           the value of the
                           kern.geom.raid3.stat.parity_mismatch sysctl is
                           increased.  One cannot use this option if the -r
                           option is also specified.

     clear          Clear metadata on the given providers.

     configure      Configure the given device.

                    Additional options include:

                    -a     Turn on autosynchronization of stale components.

                    -d     Do not hardcode providers' names in metadata.

                    -h     Hardcode providers' names in metadata.

                    -n     Turn off autosynchronization of stale components.

                    -r     Turn on round-robin reading.

                    -R     Turn off round-robin reading.

                    -w     Turn on verify reading.

                    -W     Turn off verify reading.

     rebuild        Rebuild the given component forcibly.  If
                    autosynchronization was not turned off for the given
                    device, this command should be unnecessary.

     insert         Add the given component to the existing array, if one of
                    the components was removed previously with the remove
                    command or if one component is missing and will not be
                    connected again.

                    Additional options include:

                    -h     Hardcode providers' names in metadata.

     remove         Remove the given component from the given array and clear
                    metadata on it.

     stop           Stop the given arrays.

                    Additional options include:

                    -f     Stop the given array even if it is opened.

     list           See geom(8).

     status         See geom(8).

     load           See geom(8).

     unload         See geom(8).

     Additional options include:

     -v     Be more verbose.

     Exit status is 0 on success, and 1 if the command fails.

     Use 3 disks to setup a RAID3 array (with the round-robin reading
     feature).  Create a file system, mount it, then unmount it and stop

           graid3 label -v -r data da0 da1 da2
           newfs /dev/raid3/data
           mount /dev/raid3/data /mnt
           umount /mnt
           graid3 stop data
           graid3 unload

     Create a RAID3 array, but do not use the automatic synchronization
     feature.  Rebuild parity component:

           graid3 label -n data da0 da1 da2
           graid3 rebuild data da2

     Replace one data disk with a brand new one:

           graid3 remove -n 0 data
           graid3 insert -n 0 data da5

     geom(4), geom(8), mount(8), newfs(8), umount(8), vinum(8)

     The graid3 utility appeared in FreeBSD 5.3.

     Pawel Jakub Dawidek <>

     There should be a section with an implementation description.

     Documentation for sysctls kern.geom.raid3.* is missing.

FreeBSD 11.0-PRERELEASE         August 22, 2004        FreeBSD 11.0-PRERELEASE


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