Vmdk Better - Delta

All subsequent "write" operations from the Guest OS are diverted to this delta file.

| Type | Suffix | Writable | Sparse | Purpose | |------|--------|----------|--------|---------| | | -flat.vmdk | Yes | No | Primary, pre-allocated disk | | Delta VMDK | -delta.vmdk | Yes | Yes | Snapshot/linked clone changes | | Sparse VMDK | .vmdk (no suffix) | Yes | Yes | Thin-provisioned primary disk | | Base VMDK | .vmdk + -flat.vmdk | No* | Varies | Parent for snapshots (*read-only when child exists) | delta vmdk

This process merges the data from the -delta.vmdk back into the parent -flat.vmdk and then deletes the delta file. All subsequent "write" operations from the Guest OS

The (often appearing as vmname-00000x-delta.vmdk ) is a specialized virtual disk file created by VMware ESXi whenever a snapshot is taken of a virtual machine. It serves as a "redo log" that captures all new data written to the disk after the snapshot point, ensuring the original base disk remains unchanged and "frozen" in time. Core Mechanism: How Delta Disks Work It serves as a "redo log" that captures

Think of it like tracing paper over a book: You read the tracing paper first; if nothing is written there, you look at the book underneath. Any new writing goes only on the tracing paper.

A small text file containing metadata, such as the disk geometry and the "parent CID" (Content ID) used to link the delta to its parent disk.