CONTENTS

SYNOPSIS

DESCRIPTION

The first argument to gmirror indicates an action to be performed:

label	Create a mirror. The order of components is important, because a component’s priority is based on its position (starting from 0). The component with the biggest priority is used by the prefer balance algorithm and is also used as a master component when resynchronization is needed, e.g. after a power failure when the device was open for writing. Additional options include:

-b balance	Specifies balance algorithm to use, one of:
load	Read from the component with the lowest load.
prefer	Read from the component with the biggest priority.
round-robin	Use round-robin algorithm when choosing component to read.
split	Split read requests, which are bigger than or equal to slice size on N pieces, where N is the number of active components.

-h	Hardcode providers’ names in metadata.
-n	Turn off autosynchronization of stale components.
-s slice	When using the split balance algorithm and an I/O READ request is bigger than or equal to this value, the I/O request will be split into N pieces, where N is the number of active component.

clear	Clear metadata on the given providers.
configure	Configure the given device. Additional options include:
-a	Turn on autosynchronization of stale components.
-b balance	Specifies balance algorithm to use.
-d	Do not hardcode providers’ names in metadata.
-h	Hardcode providers’ names in metadata.
-n	Turn off autosynchronization of stale components.
-s slice	Specifies slice size for split balance algorithm.

rebuild	Rebuild the given mirror components forcibly. If autosynchronization was not turned off for the given device, this command should be unnecessary.
insert	Add the given component(s) to the existing mirror. Additional options include:

-h	Hardcode providers’ names in metadata.
-i	Mark component(s) as inactive immediately after insertion.
-p priority	Specifies priority of the given component(s).

remove	Remove the given component(s) from the mirror and clear metadata on it.
activate	Activate the given component(s), which were marked as inactive before.
deactivate	Mark the given component(s) as inactive, so it will not be automatically connected to the mirror.
forget	Forget about components which are not connected. This command is useful when a disk has failed and cannot be reconnected, preventing the remove command from being used to remove it.
stop	Stop the given mirror. Additional options include:

-f	Stop the given mirror even if it is opened.

dump	Dump metadata stored on the given providers.
list	See geom(8).
status
	See geom(8).
load	See geom(8).
unload
	See geom(8).

EXAMPLES

Create a mirror on disk with valid data (note that the last sector of the disk will be overwritten). Add another disk to this mirror, so it will be synchronized with existing disk:
gmirror label -v -b round-robin data da0
gmirror insert data da1

Create a mirror, but do not use automatic synchronization feature. Add another disk and rebuild it:
gmirror label -v -n -b load data da0 da1
gmirror insert data da2
gmirror rebuild data da2

One disk failed. Replace it with a brand new one:
gmirror forget data
gmirror insert data da1

HISTORY

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