Disk group alignment constraints on volumes

Certain constraints apply to the length of volumes and to the numeric values of size attributes that apply to volumes. If a volume is created in a disk group that is compatible with the Cross-platform Data Sharing (CDS) feature, the volume's length and the values of volume attributes that define the sizes of objects such as logs or stripe units, must be an integer multiple of the alignment value of 8 blocks (8 kilobytes). If the disk group is not compatible with the CDS feature, the volume's length and attribute size values must be multiples of 1 block (1kilobyte).

To discover the value in blocks of the alignment that is set on a disk group, use this command:

# vxprint -g diskgroup -G -F %align

By default, vxassist automatically rounds up the volume size and attribute size values to a multiple of the alignment value. (This is equivalent to specifying the attribute dgalign_checking=round as an additional argument to the vxassist command.)

If you specify the attribute dgalign_checking=strict to vxassist, the command fails with an error if you specify a volume length or attribute size value that is not a multiple of the alignment value for the disk group.