Recover Vmfs Datastore Access

It was 2:00 AM on a Tuesday—the universal witching hour for IT disasters. Maya, a senior storage administrator, was jolted awake not by her pager, but by the eerie silence of her monitoring dashboard going dark. Then the texts came: “ESXi hosts lost connectivity to datastore ‘Prod-HighSpeed’.”

Step 3: Deeper scan. She ran vmfs6-recover (part of vmfs-tools ). It parsed backup VMFS metadata—the first copy of the file system descriptor had been overwritten when the host re-scanned the "new" LUN, but VMware stores a second copy at offset 512 MB.

Maya stared at the now-green dashboard. Somewhere in the datacenter, a disk blinked its steady heartbeat. She smiled. Another VMFS ghost story, beaten by knowing exactly where VMware hides its backup superblocks. recover vmfs datastore

The command returned: Superblock updated. Checking file system...

She logged in. Heart sank. The 12-TB VMFS volume—hosting a real-time fraud detection system—wasn’t just offline. It was gone. ls -la /vmfs/volumes/ showed only the local datastore. Someone (an intern following an outdated runbook) had accidentally zapped the LUN mapping from the SAN side, then re-presented it—but as a new device signature. It was 2:00 AM on a Tuesday—the universal

Step 4: She used dd to copy that backup block over the primary superblock (after making a full LUN image with ddrescue to a separate 12-TB drive—insurance). # dd if=/dev/sde1 bs=1M skip=512 count=1 of=primary_superblock_backup.bin Then, using vimfstools (from a recovered ESXi maintenance mode session): # vmkfstools -B recover /vmfs/devices/disks/naa.6000...:1

Step 1: Identify the device. fdisk -l showed /dev/sde as 12 TB, with partition 1 (VMFS) starting at sector 2048. Good—partition still there. She ran vmfs6-recover (part of vmfs-tools )

Step 6: Re-register each VM from the configuration file: # find /vmfs/volumes/Prod-HighSpeed -name "*.vmx" -exec vim-cmd solo/registervm {} \;