Интерактивная система просмотра системных руководств (man-ов)
gvirstor (8)
>> gvirstor (8) ( FreeBSD man: Команды системного администрирования )
BSD mandoc
NAME
gvirstor
- provides virtual data storage geom
SYNOPSIS
label
[-hv
]
[-s virsize
]
[-m chunksize
]
nameprov ... stop
[-fv
]
name ... add
[-vh
]
name prov ... remove
[-v
]
name prov ... clear
[-v
]
prov ... dumpprov ... list status load unload
DESCRIPTION
The
utility is used for setting up a storage device of arbitrary large size (for example,
several TB), consisting of an arbitrary number of physical storage devices with
total size <= the virtual size. Data for the virtual devices will be allocated from
physical devices on demand. In short, this is the virtual storage functionality.
The first argument to
indicates an action to be performed:
label
Set up a virtual device from the given components with the specified
name
Metadata are stored in the last sector of every component.
Argument
virsize
is the size of new virtual device, with default being 2 TiB (2097152 MiB).
Argument
chunksize
is the chunk size, with default being 4 MiB (4096 KiB).
The default is thus "-s 2097152 -m 4096".
stop
Turn off an existing virtual device by its
name
This command does not touch on-disk metadata.
As with other GEOM classes, stopped geoms cannot be started manually.
add
Adds new components to existing virtual device by its
name
The specified virstor device must exist and be active (i.e.
module loaded, device present in /dev).
remove
Removes components from existing virtual device by its
name
Only unallocated providers can be removed.
Force the removal of the specified virtual device.
-h
Hardcode providers' names in metadata.
-v
Be more verbose.
EXIT STATUS
Exit status is 0 on success, and 1 if the command fails.
EXAMPLES
The following example shows how to create a virtual device of default size
(2 TiB), of default chunk (extent) size (4 MiB), with two physical devices for
backing storage.
From now on, the virtual device will be available via the
/dev/virstor/mydata
device entry.
To add a new physical device / provider to an active virstor device:
gvirstor add mydata ad8
This will add physical storage (from ad8) to
/dev/virstor/mydata
device.
To see device status information (including how much physical storage
is still available for the virtual device), use:
gvirstor list
All standard
geom(8)
subcommands (e.g. "status", "help") are also supported.
This sysctl controls verbosity of the kernel module, in the range
1 to 15. Messages that are marked with higher verbosity levels than
this are supressed. Default value is 5 and it's not
recommented to set this tunable to less than 2, because level 1 messages
are error events, and level 2 messages are system warnings.
int kern.geom.virstor.chunk_watermark
Value in this sysctl sets warning watermark level for physical chunk usage
on a single component. The warning is issued when a virstor component
has less than this many free chunks (default 100).
int kern.geom.virstor.component_watermark
Value in this sysctl sets warning watermark level for component usage.
The warning is issed when there are less than this many unallocated
components (default is 1).
All these sysctls are also available as
loader(8)
tunables.
LOG MESSAGES
kernel module issues log messages with prefixes in standardised format,
which is useful for log message filtering and dispatching. Each message
line begins with
GEOM_VIRSTOR[%d]:
The number (%d) is message verbosity / importance level, in the range
1 to 15. If a message filtering, dispatching or operator alert system is
used, it is recommended that messages with levels 1 and 2 be taken
seriously (for example, to catch out-of-space conditions as set by
watermark sysctls).
Commands "add" and "remove" contain unavoidable critical sections
which may make the virstor device unusable if a power failure (or
other disruptive event) happens during their execution.
It's recommended to run them when the system is quiescent.
AUTHOR
An Ivan Voras Aq [email protected]
Sponsored by Google Summer of Code 2006
