254Creating volumes

Creating a striped volume

You can specify the disks on which the volumes are to be created by including the disk names on the command line. For example, to create a 30-gigabyte striped volume on three specific disks, mydg03, mydg04, and mydg05, use the following command:

#vxassist -b -g mydg make stripevol 30g layout=stripe \ mydg03 mydg04 mydg05

To change the number of columns or the stripe width, use the ncolumn and stripeunit modifiers with vxassist. For example, the following command creates a striped volume with 5 columns and a 32-kilobyte stripe size:

#vxassist -b -g mydg make stripevol 30g layout=stripe \ stripeunit=32k ncol=5Creating a mirrored-stripe volumeA mirrored-stripe volume mirrors several striped data plexes.

Note: A mirrored-stripe volume requires space to be available on at least as many disks in the disk group as the number of mirrors multiplied by the number of columns in the volume.

To create a striped-mirror volume, use the following command:

#vxassist [-b] [-g diskgroup] make volume length \ layout=mirror-stripe [nmirror=number_mirrors] \ [ncol=number_of_columns] [stripewidth=size]

Alternatively, first create a striped volume, and then mirror it as described in “Adding a mirror to a volume” on page 271. In this case, the additional data plexes may be either striped or concatenated.

Creating a striped-mirror volume

A striped-mirror volume is an example of a layered volume which stripes several underlying mirror volumes.

Note: A striped-mirror volume requires space to be available on at least as many disks in the disk group as the number of columns multiplied by the number of stripes in the volume.

To create a striped-mirror volume, use the following command:

#vxassist [-b] [-g diskgroup] make volume length \ layout=stripe-mirror [nmirror=number_mirrors] \ [ncol=number_of_columns] [stripewidth=size]

By default, VxVM attempts to create the underlying volumes by mirroring subdisks rather than columns if the size of each column is greater than the value