Contidos dentroLocalizar Mais DocumentaçãoDestaques de Recursos de Suporte |  Fazer download desta apostila em PDF (1709 KB)
Managing ZFS PropertiesDataset properties are managed through the zfs command's set, inherit, and get subcommands. Setting ZFS PropertiesYou can use the zfs set command to modify any settable dataset property. Or, you can use the zfs create command to set properties when the dataset is created. For a list of settable dataset properties, see Settable ZFS Native Properties. The zfs set command takes a property/value sequence in the format of property=value and a dataset name. The following example sets the atime property to off for tank/home. Only one property can be set or modified during each zfs set invocation.
In addition, any file system property can be set when the file system is created. For example:
You can specify numeric properties by using the following easy to understand suffixes (in order of magnitude): BKMGTPEZ. Any of these suffixes can be followed by an optional b, indicating bytes, with the exception of the B suffix, which already indicates bytes. The following four invocations of zfs set are equivalent numeric expressions indicating that the quota property be set to the value of 50 Gbytes on the tank/home/marks file system:
Values of non-numeric properties are case-sensitive and must be lowercase, with the exception of mountpoint and sharenfs. The values of these properties can have mixed upper and lower case letters. For more information about the zfs set command, see zfs(1M). Inheriting ZFS PropertiesAll settable properties, with the exception of quotas and reservations, inherit their value from their parent, unless a quota or reservation is explicitly set on the child. If no ancestor has an explicit value set for an inherited property, the default value for the property is used. You can use the zfs inherit command to clear a property setting, thus causing the setting to be inherited from the parent. The following example uses the zfs set command to turn on compression for the tank/home/bonwick file system. Then, zfs inherit is used to unset the compression property, thus causing the property to inherit the default setting of off. Because neither home nor tank have the compression property set locally, the default value is used. If both had compression on, the value set in the most immediate ancestor would be used (home in this example).
The inherit subcommand is applied recursively when the -r option is specified. In the following example, the command causes the value for the compression property to be inherited by tank/home and any descendents it might have.
Note – Be aware that the use of the -r option clears the current property setting for all descendent datasets. For more information about the zfs command, see zfs(1M). Querying ZFS PropertiesThe simplest way to query property values is by using the zfs list command. For more information, see Listing Basic ZFS Information. However, for complicated queries and for scripting, use the zfs get command to provide more detailed information in a customized format. You can use the zfs get command to retrieve any dataset property. The following example shows how to retrieve a single property on a dataset:
The fourth column, SOURCE, indicates where this property value has been set. The following table defines the meaning of the possible source values. Table 6–3 Possible SOURCE Values (zfs get)
You can use the special keyword all to retrieve all dataset properties. The following examples use the all keyword to retrieve all existing dataset properties:
The -s option to zfs get enables you to specify, by source type, the properties to display. This option takes a comma-separated list indicating the desired source types. Only properties with the specified source type are displayed. The valid source types are local, default, inherited, temporary, and none. The following example shows all properties that have been locally set on pool.
Any of the above options can be combined with the -r option to recursively display the specified properties on all children of the specified dataset. In the following example, all temporary properties on all datasets within tank are recursively displayed:
A recent feature enables you to make queries with the zfs get command without specifying a target file system, which means it operates on all pools or file systems. For example:
For more information about the zfs get command, see zfs(1M). Querying ZFS Properties for ScriptingThe zfs get command supports the -H and -o options, which are designed for scripting. The -H option indicates that any header information should be omitted and that all white space be replaced with a tab. Uniform white space allows for easily parseable data. You can use the -o option to customize the output. This option takes a comma-separated list of values to be output. All properties defined in Introducing ZFS Properties, along with the literals name, value, property and source can be supplied in the -o list. The following example shows how to retrieve a single value by using the -H and -o options of zfs get.
The -p option reports numeric values as their exact values. For example, 1 Mbyte would be reported as 1000000. This option can be used as follows:
You can use the -r option along with any of the above options to recursively retrieve the requested values for all descendents. The following example uses the -r, -o, and -H options to retrieve the dataset name and the value of the used property for export/home and its descendents, while omitting any header output:
|
|||||||||||||||||||||||||
|