Described is a technology by which a virtual hard disk is able to continue servicing virtual disk I/O (reads and writes) while a meta-operation (e.g., copying, moving, deleting, merging, compressing, defragmenting, cryptographic signing, lifting, dropping, converting, or compacting virtual disk data) is performed on the virtual disk. The servicing of virtual disk I/Os may be coordinated with meta-operation performance, such as by throttling and/or prioritizing the virtual disk I/Os. Also described is performing a meta-operation by manipulating one or more de-duplication data structures.