GRAID3(8) FreeBSD System Manager's Manual GRAID3(8)
NAME
graid3 - control utility for RAID3 devices
SYNOPSIS
graid3 label [-Fhnrvw] [-s blocksize] name prov prov prov ...
graid3 clear [-v] prov ...
graid3 configure [-adfFhnrRvwW] 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
DESCRIPTION
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:
-F
Do not synchronize after a power failure or system crash.
Assumes device is in consistent state.
-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 specified.
-s
Manually specify array block size. Block size will be set
equal to least common multiple of all component's sector
sizes and specified value. Note that array sector size
calculated as multiple of block size and number of regular
data components. Big values may decrease performance and
compatibility, as all I/O requests have to be multiple of
sector size.
-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.
-f
Synchronize device after a power failure or system crash.
-F
Do not synchronize after a power failure or system crash.
Assumes device is in consistent state.
-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.
If no number is given, new component will be added instead of
first missed component.
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
Exit status is 0 on success, and 1 if the command fails.
EXAMPLES
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
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 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
SEE ALSO
geom(4), geom(8), mount(8), newfs(8), umount(8)
HISTORY
The graid3 utility appeared in FreeBSD 5.3.
AUTHORS
Pawel Jakub Dawidek <pjd@FreeBSD.org>
BUGS
There should be a section with an implementation description.
Documentation for sysctls kern.geom.raid3.* is missing.
FreeBSD 15.1-STABLE-HBSD January 23, 2025 GRAID3(8)