"Server is slow. Throwing I/O errors. Tried to restart; now it won't boot."
for vmdk in $(find $DATASTORE_PATH -name " .vmdk" ! -name " -flat.vmdk"); do echo "Checking: $vmdk" >> $LOG_FILE
The CID (Content ID) was reset to fffffffe — a flag meaning "unknown or corrupted parent." The flat extent is intact, but the mapping is blind.
vmkfstools -x repair /vmfs/volumes/datastore01/server01/server01.vmdk Output: "Failed to repair disk. Disk chain is inconsistent."
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.
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.
