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 ... |
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.
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),
gvinum(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.
