| Main index | Section 8 | Options |
The first argument to gvirstor indicates an action to be performed:
| label |
Set up a virtual device from the given components with the specified
name.
Metadata is stored in the last sector of every component.
Argument
|
| stop | Turn off an existing virtual device with the given name. This command does not touch on-disk metadata. As with other GEOM classes, stopped geoms cannot be started manually. |
| destroy | |
| Same as stop. | |
| add | Adds new components to existing virtual device with the given name. The specified virstor device must exist and be active (i.e. module loaded, device present in /dev). This action can be safely performed while the virstor device is in use ("hot "operation). |
| remove | |
| Removes components from existing virtual device with the given name. Only unallocated providers can be removed. | |
| clear | Clear metadata on the given providers. |
| dump | Dump metadata stored on the given providers. |
| list | See geom(8). |
| status | |
| See geom(8). | |
| load | See geom(8). |
| unload | |
| See geom(8). | |
Additional options:
| | |
| Force the removal of the specified virtual device. | |
| | |
| Hardcode providers' names in metadata. | |
| | |
| Be more verbose. | |
gvirstor label -v mydata /dev/ada4 /dev/ada6 newfs /dev/virstor/mydata
From now on, the virtual device will be available via the /dev/virstor/mydata device entry. To add a new physical device / component to an active virstor device:
gvirstor add mydata ada8
This will add physical storage of ada8 to /dev/virstor/mydata device.
To see the 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.
int kern.geom.virstor.debug
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 suppressed. Default value is 5 and it is not recommended 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 issued when there are less than this many unallocated components (default is 1).
All these sysctls are also available as loader(8) tunables.
gvirstor kernel module issues log messages with prefixes in standardized 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.
Sponsored by Google Summer of Code 2006.
Note that gvirstor has nontrivial interaction with file systems which initialize a large number of on-disk structures during newfs. If such file systems attempt to spread their structures across the drive media (like UFS/UFS2 does), their efforts will be effectively foiled by sequential allocation of chunks in gvirstor and all their structures will be physically allocated at the start of the first virstor component. This could have a significant impact on file system performance (which can in some rare cases be even positive).
| GVIRSTOR (8) | October 1, 2013 |
| Main index | Section 8 | Options |
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