Recovery - Vmfs

: Never trust a single VMFS datastore – replication and backups remain the only guaranteed recovery path. This write-up is for authorized forensic analysis and disaster recovery only. Always comply with software licensing and data privacy laws.

dd if=vmfs_disk.dd bs=512 | strings -n 8 | grep -E "FD.4,8VMFS" Manually map FD number → block pointers. If you have the FD for a flat VMDK ( -flat.vmdk ), you can extract its data blocks sequentially using the FB table. vmfs recovery

vmfs-fuse -o ro /dev/loop0 /mnt/recovery If that fails, carve small files by known headers ( #! for VMX, KDMV for VMDK descriptor). Situation : An administrator ran vmkfstools -C vmfs5 /dev/disks/... on a datastore containing 12 production VMs. : Never trust a single VMFS datastore –

sgrep -b 'VMFS5' vmfs_disk.dd FDs start with a known pattern (e.g., FD 00 00 01 for VMFS5). Scan the entire disk: dd if=vmfs_disk

This write-up outlines a systematic methodology for recovering data from damaged or inaccessible VMFS datastores (VMFS3, VMFS5, VMFS6) using low-level disk analysis and specialized recovery tools. | Symptom | Possible Cause | |---------|----------------| | Datastore appears as "not mounted" or "unmounted" in vSphere | Corrupt heartbeats or partition table | | VMs missing from inventory but .vmx/.vmdk files visible via CLI | Lost directory entries or corrupt file descriptors (FDs) | | Unable to power on VM: "File system specific error" | Corrupt VMFS metadata (FB, PB, or resource allocation) | | Entire LUN shows as raw or snapshot LUN | Overwritten VMFS superblock or partition table | | Deleted VMDKs still consuming space | Orphaned file blocks without FD links | 3. VMFS Metadata Structures (Recovery Essentials) Understanding key on-disk structures is critical for manual recovery:

Example (pseudo‑script logic):