The flat file sits on a physical datastore — VMFS, NFS, vSAN. The hypervisor interposes : the guest’s LBA 0 is not the file’s byte 0? Wait — with a flat VMDK, it is . Direct mapping. No COW, no delta. Pure, linear, dangerous.
A small plain-text file that acts as a "roadmap," containing IDs, disk geometry, and hardware versions.
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. vmdk flat file
The primary disadvantage of the flat file is inflexibility. If you allocate a 500 GB flat VMDK, that 500 GB is consumed on the datastore immediately, even if the VM only has 10 GB of data. This leads to lower storage efficiency compared to Thin Provisioning.
The VM’s BIOS wakes. The virtual LSI Logic controller initializes. A master boot record is written to sector 0 — bytes 0xFA 0x31 0xC0 0x8E 0xD8 . The flat file’s heart beats for the first time: . The flat file sits on a physical datastore
Because flat files are monolithic and large, they are highly susceptible to filesystem fragmentation on the datastore (VMFS). Heavy fragmentation can degrade I/O performance. Administrators must use VMFS defragmentation tools cautiously to mitigate this.
A vmkfstools -i source-flat.vmdk clone-flat.vmdk — and the flat file is duplicated, byte-for-byte. Now two separate VMs believe they own the same past. Each will diverge. Direct mapping
The flat file is essentially a binary file structured to mimic a physical hard drive. It reads and writes data in blocks. If a Virtual Machine has a 100 GB hard drive, the flat.vmdk file will be exactly 100 GB in size, regardless of how much data is actually inside the VM (in the case of Thick Provisioning).
The flat file sits on a physical datastore — VMFS, NFS, vSAN. The hypervisor interposes : the guest’s LBA 0 is not the file’s byte 0? Wait — with a flat VMDK, it is . Direct mapping. No COW, no delta. Pure, linear, dangerous.
A small plain-text file that acts as a "roadmap," containing IDs, disk geometry, and hardware versions.
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 primary disadvantage of the flat file is inflexibility. If you allocate a 500 GB flat VMDK, that 500 GB is consumed on the datastore immediately, even if the VM only has 10 GB of data. This leads to lower storage efficiency compared to Thin Provisioning.
The VM’s BIOS wakes. The virtual LSI Logic controller initializes. A master boot record is written to sector 0 — bytes 0xFA 0x31 0xC0 0x8E 0xD8 . The flat file’s heart beats for the first time: .
Because flat files are monolithic and large, they are highly susceptible to filesystem fragmentation on the datastore (VMFS). Heavy fragmentation can degrade I/O performance. Administrators must use VMFS defragmentation tools cautiously to mitigate this.
A vmkfstools -i source-flat.vmdk clone-flat.vmdk — and the flat file is duplicated, byte-for-byte. Now two separate VMs believe they own the same past. Each will diverge.
The flat file is essentially a binary file structured to mimic a physical hard drive. It reads and writes data in blocks. If a Virtual Machine has a 100 GB hard drive, the flat.vmdk file will be exactly 100 GB in size, regardless of how much data is actually inside the VM (in the case of Thick Provisioning).