HP SAN Virtualization Services Platform - Manual (Page 266)

Built-in capacity protection
VSM features a built-in protection mechanisms for storage pools running out of free capacity. The
objective of the protection mechanisms is to ensure that storage pools always have enough free
capacity to handle the expansion requests of snapshot temporary virtual disks (or else, write I/Os will
fail).
For details, see “ Built-in capacity protection ” on page 238.
Using migration 266