graid3(8)

NAME

graid3 - control utility for RAID3 devices

SYNOPSIS

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

DESCRIPTION

The graid3 utility is used for RAID3 array configuration.

After a device
is created, all components are detected and configured auto

matically.
All operations such as failure detection, stale component

detection,
rebuild of stale components, etc. are also done automatical

ly. 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 per

formed:

label Create a RAID3 device. The last given compo

nent will con

tain 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 par

ity component
is not used at all for reading opera

tions 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 slow

er. One cannot use this option if the -w option

is also specified.

-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 op

tion 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 au

tosynchroniza

tion was not turned off for the given device,

this command
should be unnecessary.

insert Add the given component to the existing ar

ray, 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 ar

ray 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 synchro

nization 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), vinum(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 descrip

tion.

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

BSD August 22, 2004

BSD