Here is the deep story of the VMDK flat file, told from its own silent perspective. In the beginning, there was a creation command: vmkfstools -c 40GB -a lsilogic thin.vmdk . But the flat file was not thin. It was allocated in full — every byte of its 40 billion bytes claimed from the hypervisor’s namespace. A zeroed expanse, a desert of nulls.
One day, the clone’s admin runs zerofree on the guest’s ext4 partition. Zeros overwrite unused blocks. But the zeros are data now. The ghost is exorcised — replaced by the void. But the void is still a story: “Someone cared enough to wipe me.” A flat file cannot snapshot itself. It needs a delta VMDK — a sparse child. But when a snapshot is taken, the flat file becomes read-only forever. Frozen in amber. All new writes go to -delta.vmdk . vmdk flat file
When the snapshot is finally deleted, the hypervisor’s vmfs reaps the flat file. Its blocks are freed, overwritten by new VMDKs. But for a brief time after deletion, the raw sectors on the SSD still hold the MBR, the superblocks, the half-deleted spreadsheets. Here is the deep story of the VMDK
And the analyst whispers: “You were not just storage. You were memory.” It was allocated in full — every byte
When a guest OS deletes a file, it merely unlinks an inode. The flat file’s sectors remain pristine with the old data — a photograph of a document that was “shredded.” Over time, new writes overlay these sectors. But until overwritten, the ghost persists.
: The underlying RAID’s URE (unrecoverable read error) strikes. The guest reads sector 5,000,000. The hypervisor returns -1 . The VM bluescreens. The flat file now has a scar — a hole where data used to be.
The flat file watches, unable to change, as the guest OS installs updates, deletes logs, creates users. It is a museum diorama of a past state. If the snapshot chain is never committed, the flat file will drift into obsolescence — a perfect copy of an irrelevant moment.