To create a BCV clone, EVM first examines the source unit configuration. When two or more redundant members (three or more mirror set members) already exist, EVM immediately splits off one of the members to create the BCV clone. With the quick clone method, creation of the BCV is nearly instantaneous.
By comparison, creating a BCV clone of a source unit that has one or no redundant members (two-member mirror sets, stripesets and JBODs ) is usually slower. This is because EVM must add a redundant member and wait for the members to normalize before it can split off a member to create the BCV.
No matter which clone creation method EVM uses, the corresponding EVM undo-job (when run) will return settings and disk resources to the configuration that existed just before the job started.