Vmdk Corrupted May 2026

[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:

"Server is slow. Throwing I/O errors. Tried to restart; now it won't boot."

# Disk DescriptorFile version=1 CID=fffffffe parentCID=fffffffe createType="vmfs" RW 419430400 VMFS "server01-flat.vmdk" vmdk corrupted

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.

I open the server01.vmdk (descriptor file) in a terminal. [SUCCESS] Grain table rebuilt

# 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

Scenario: VMware ESXi environment, version 7.0.3. VM: Legacy SQL Server. The SQL database performs a recovery on mount

vmkfstools -x repair /vmfs/volumes/datastore01/server01/server01.vmdk Output: "Failed to repair disk. Disk chain is inconsistent."