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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 [prov [...]]
     graid3 clear [-v] prov [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 [name [...]]
     graid3 list [name [...]]
     graid3 load [-v]
     graid3 unload [-v]

     The graid3 utility is used for RAID3 arrays configuration.  After a
     device creation, all components are detected and configured
     automatically.  All operations like failure detection, stale components
     detection, rebuild of stale components etc. are done automatically as
     well.  The graid3 utility uses on-disk metadata (the last provider's
     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, all the rest - regular data.  Number
                    of components has to be equal to 3, 5, 9, 17, etc. (2^n +

                    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 parity component is
                           not used at all for reading operations when device
                           is in complete state.  With this option specified
                           random I/O read operations are even 40% faster, but
                           sequential reads are slower.  One cannot not use
                           this options if -w option is also specified.

                    -w     Use verify reading feature.  When reading from
                           device in complete state, read data also from
                           parity component and verify the data by comparing
                           XORed regular data with parity data.  If
                           verification fails, EIO error is returned and value
                           of sysctl kern.geom.raid3.stat.parity_mismatch is
                           increased.  One cannot not use this options if -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 wasn't turn off for the given device,
                    this command hopefully will not be used.

     insert         Add the given component to the existing array, if one of
                    the component was removed previously with the remove
                    command or 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           List every currently configured devices, if a list of
                    devices is passed as a parameter then only those devices
                    will be shown.

     load           Load geom_raid3.ko kernel module.

     unload         Unload geom_raid3.ko kernel module.

     Additional options include:

     -v     Be more verbose.

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

           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 automatic sunchronization 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

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

     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 implementation description.

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


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