HP StorageWorks SAN Virtualization Services Platform Manager user guide (5697-0295, January 2010)

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 migration266