fsck on a VMFS partition can lead to further data corruption as it does not recognize the VMFS metadata structure. Broadcom Community +2 2. Diagnosis with vOMA VMware provides the vSphere On-disk Metadata Analyzer (vOMA) to identify metadata inconsistencies. This tool is primarily for read-only diagnosis to check if a volume is "fixable". Broadcom Community Common vOMA Command Structure: bash voma -m vmfs -f check -d /vmfs/devices/disks/[naa_id]:[partition] Use code with caution. Copied to clipboard Note: While vOMA can detect errors, VMware documentation often advises that significant corruption may require rebuilding the volume rather than manual in-place repair. Broadcom Community +1 3. Data Recovery Strategies When a VMFS volume is corrupted and cannot be mounted, the following recovery paths are recommended: 11 sites How to fsck (repair vmfs 3 volume) with ESXi? Nov 19, 2010 —
Executive Summary Verdict: Use with extreme caution. The fsck tool for VMFS (VMware Virtual Machine File System) is not a "fix-it-all" utility like standard Linux fsck . It is a low-level consistency check that can result in data loss if used incorrectly. It should only be used as a last resort when the VMFS datastore is corrupted and mounting fails, and you have no other recovery options (backups or snapshot restoration) available.
Detailed Review 1. Usage & Syntax Unlike standard Linux filesystems, you do not run fsck on the block device directly in a way that automatically fixes things.
Command: vmkfstools -D /vmfs/devices/disks/<deviceID> fsck vmfs repair
Note: Many users confuse the Linux fsck command with VMFS tools. On ESXi, the tool primarily used for checking the filesystem state is vmkfstools .
The "Check" Only Mode: You can run vmkfstools -D -e /vmfs/devices/disks/<deviceID> to check for errors without writing changes (read-only). Force Repair: There is no simple "yes, fix it" flag. The repair process is often destructive or involves running specific advisory commands provided by VMware Support.
2. Performance & Efficiency
Speed: The checking process is I/O intensive. On large datastores (multi-terabyte), a full consistency check can take hours, depending on the underlying storage speed. System Impact: Running this process puts a significant load on the ESXi host's storage stack. It is recommended to run this during maintenance windows with no running VMs on the affected datastore (if possible).
3. Effectiveness (Does it work?)
Metadata Corruption: It is moderately effective at resolving minor metadata inconsistencies (e.g., heartbeats, lock states) that prevent a datastore from mounting. Severe Corruption: It is generally ineffective for severe corruption (e.g., damaged LUN headers, massive pointer corruption). In these cases, fsck may report success but the datastore will still be empty or fail to mount. False Positives: It sometimes flags legitimate but complex snapshot chains as errors. fsck on a VMFS partition can lead to
4. The "Danger Zone" (Cons) This is the most critical part of the review:
Risk of Data Loss: Running repair operations on a VMFS filesystem can result in the deletion of files (VMDKs) that the tool deems "inconsistent" or "orphaned." No Guarantees: The tool prioritizes the integrity of the filesystem structure over the integrity of the data within it. Unsupported Actions: Forcing repairs without guidance from VMware Support often voids the possibility of professional data recovery later.