258Creating volumesCreating a volume using vxmake

Tag names and tag values are case-sensitive character strings of up to 256 characters. Tag names can consist of letters (A through Z and a through z), numbers (0 through 9), dashes (-), underscores (_) or periods (.) from the ASCII character set. A tag name must start with either a letter or an underscore. Tag values can consist of any character from the ASCII character set with a decimal value from 32 through 127. If a tag value includes any spaces, use the vxassist settag command to set the tag on the newly created volume.

Dotted tag hierarchies are understood by the list operation. For example, the listing for tag=a.b includes all volumes that have tag names that start with a.b.

The tag names site, udid and vdid are reserved and should not be used. To avoid possible clashes with future product features, it is recommended that tag names do not start with any of the following strings: asl, be, isp, nbu, sf,

symc or vx.See “Setting tags on volumes” on page 288.

Creating a volume using vxmake

As an alternative to using vxassist, you can create a volume using the vxmake command to arrange existing subdisks into plexes, and then to form these plexes into a volume. Subdisks can be created using the method described in “Creating subdisks” on page 215. The example given in this section is to create a RAID-5 volume using vxmake.

Creating a RAID-5 plex for a RAID-5 volume is similar to creating striped plexes, except that the layout attribute is set to raid5. Subdisks can be implicitly associated in the same way as with striped plexes. For example, to create a four- column RAID-5 plex with a stripe unit size of 32 sectors, use the following command:

#vxmake -g mydg plex raidplex layout=raid5 stwidth=32 \ sd=mydg00-01,mydg01-00,mydg02-00,mydg03-00

Note that because four subdisks are specified, but the number of columns is not specified, the vxmake command assumes a four-column RAID-5 plex and places one subdisk in each column. Striped plexes are created using the same method except that the layout is specified as stripe. If the subdisks are to be created and added later, use the following command to create the plex:

#vxmake -g mydg plex raidplex layout=raid5 ncolumn=4 stwidth=32

Note: If no subdisks are specified, the ncolumn attribute must be specified. Subdisks can be added to the plex later using the vxsd assoc command (see “Associating subdisks with plexes” on page 218).