Creating RAID-5 Volumes

vxassist Command and RAID-5 Volumes

Create a RAID-5 volume by using the following command:

# vxassist make volume_name length layout=raid5

For example, to create a 10M RAID-5 volume named volraid, use the following command:

# vxassist make volraid 10m layout=raid5

This command creates a RAID-5 volume with the default stripe unit size on the default number of disks.

vxmake Commandand RAID-5 Volumes

You can create a RAID-5 volume by using the vxmake command, which is similar to the command used to create other volumes (see “Creating Volumes”). Also see the vxmake(1M) manual page for details on creating other volumes. Subdisks for use in a RAID-5 volume are created using the same method as other subdisks.

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 plex raidplex layout=raid5 stwidth=32
		\sd=disk00-01,disk01-00,disk02-00,disk03-00

Note that because four subdisks are specified with no specification of columns, the vxmake command assumes a four-column RAID-5 plex and places one subdisk in each column. Striped plexes are created using this same method. If the subdisks are to be created later, use the following command to create the plex:

# vxmake plex raidplex layout=raid5 ncolumn=4 stwidth=32

	NOTE: If no subdisks are specified, the ncolumn attribute must be specified. Subdisks can later be filled in the plex by using the vxsd assoc command (see “Manipulating RAID-5 Subdisks”).

For example, to create a three-column RAID-5 plex using six subdisks, use the following command:

# vxmake plex raidplex layout=raid5 stwidth=32 \
		sd=disk00-00:0,disk01-00:1,disk02-00:2,disk03-00:0, \
		disk04-00:1,disk05-00:2

This command stacks subdisks disk00-00 and disk03-00 consecutively in column 0, subdisks disk01-00 and disk04-00 consecutively in column 1, and subdisks disk02-00 and disk05-00 in column 2. Offsets can also be specified to create sparse RAID-5 plexes, as for striped plexes.

Because log plexes are plexes without a RAID-5 layout, they can be created normally.

To create a RAID-5 volume, specify the usage type to be RAID-5 using the following command:

# vxmake -Uraid5 vol raidvol

RAID-5 plexes and RAID-5 log plexes can be associated implicitly using the following command:

# vxmake -Uraid5 vol raidvol plex=raidplex,raidlog1, raidlog2