NAME
graid3 — control utility for RAID3 devices
SYNOPSIS
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]
DESCRIPTION
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 + 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 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.
EXAMPLES
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
DIAGNOSTICS
Exit status is 0 on success, and 1 if the command fails.
SEE ALSO
geom(4), geom(8), mount(8), newfs(8), umount(8), vinum(8)
HISTORY
The graid3 utility appeared in FreeBSD 5.3.
AUTHORS
Pawel Jakub Dawidek <pjd [AT] FreeBSD.org>
BUGS
There should be a section with implementation description.
BSD Aug 22, 2004 BSD