Changing the Default Behavior of the metassist Command

You can use the volume defaults file (/etc/defaults/metassist.xml) to change the default behavior for the metassist command. By changing the defaults file, you can explicitly exclude from consideration, or include for consideration, specific disks or controllers. You can also specify requirements for most volume settings used by the metassist command.

The format of the /etc/defaults/metassist.xml is specified by the /usr/share/lib/xml/dtd/volume-defaults.dtd Document Type Definition (DTD). The format is documented in the volume-defaults(4) man page.

Changing the Volume Defaults File

Edit the volume defaults file (/etc/defaults/metassist.xml) to specify how the metassist command should behave.

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Note - When you edit the file, you must ensure that the file continues to be compliant with the /usr/share/lib/xml/dtd/volume-defaults.dtd Document Type Definition (DTD). If the XML file is not compliant with the DTD, the metassist command will fail with an error message.

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Example 23-11 Creating a Volume With Changed Defaults Using the metassist Command

Before creating a volume, edit the /etc/default/metassist.xml file to specify the default settings that you want to apply to all volumes you will create with the metassist command. In this example, the metassist command only creates volumes on controller c1 and, when creating stripes, only creates stripes with exactly four components and an interlace of value 512KB. These constraints apply to all uses of the metassist command until the /etc/default/metassist.xml file is changed again.

#  cat /etc/default/metassist.xml 
<!DOCTYPE volume-defaults SYSTEM \
"/usr/share/lib/xml/dtd/volume-defaults.dtd">

<volume-defaults>
<available name="c1" />
<stripe mincomp="4" maxcomp="4" interlace="512KB" ></stripe>
</volume-defaults>

# metassist create -s myset -S 10Gb
 

The metassist command creates a 10-Gbyte stripe, using exactly four slices and an interlace value of 512 Kbytes, as specified in the /etc/default/metassist.xml file.