Vmdk Corrupted ⭐ Must Watch

Upon attempting to power on the VM, vSphere returned the dreaded: "Failed to power on VM. The specified virtual disk needs repair (Corrupt disk)." Attempting to browse the datastore revealed the file server01_2.vmdk (the 200GB delta disk) present, but the system could not read its metadata. Part 1: The Post-Mortem Analysis What is a VMDK? A VMDK is not a single file, but a logical container. It consists of a small descriptor file (text) and a large extent file (raw data). Corruption often strikes the descriptor or the filesystem journal within the extent.

[SUCCESS] Grain table rebuilt. 1,892,471 sectors recovered. [WARNING] 204 sectors unrecoverable (log files, temporary data). The SQL database performs a recovery on mount. I lose 15 minutes of transaction log data. The business accepts the loss. To prevent this, implement a VMDK health check cron job on the ESXi host: vmdk corrupted

if [ ! -z "$FLAT_SIZE" ]; then CALC_MB=$(($FLAT_SIZE / 1024 / 1024)) echo "Health: $vmdk is $CALC_MB MB nominal." >> $LOG_FILE fi done VMDK corruption is rarely a hardware failure. It is a timing failure —where the hypervisor assumes a write completed before the storage array confirms it. The fix involves bypassing the broken descriptor and forcing a rebuild from the raw extent. Always keep a backup of the .vmdk descriptor file separately from the flat file. Upon attempting to power on the VM, vSphere

"Server is slow. Throwing I/O errors. Tried to restart; now it won't boot." A VMDK is not a single file, but a logical container

I pull the manifest. The VMDK is 2TB thin-provisioned. The VM won't boot. The backup ran six hours ago, but the differential is useless because the block map is scrambled.

Scenario: VMware ESXi environment, version 7.0.3. VM: Legacy SQL Server.

#!/bin/bash # vmdk_integrity_check.sh # Checks for early signs of VMDK corruption DATASTORE_PATH="/vmfs/volumes/VM_Storage" LOG_FILE="/var/log/vmdk_health.log"