Vmdk Corrupted May 2026

for vmdk in $(find $DATASTORE_PATH -name " .vmdk" ! -name " -flat.vmdk"); do echo "Checking: $vmdk" >> $LOG_FILE

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. vmdk corrupted

# Check for zeroed CID (Corruption flag) CID=$(grep "CID=" $vmdk | cut -d'=' -f2) if [ "$CID" == "fffffffe" ]; then echo "ALERT: $vmdk has invalid CID. Possible corruption." >> $LOG_FILE /usr/bin/vmkfstools -x check $vmdk >> $LOG_FILE fi for vmdk in $(find $DATASTORE_PATH -name "

[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: Part 1: The Post-Mortem Analysis What is a VMDK

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.

I open the server01.vmdk (descriptor file) in a terminal.

#!/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"