### Human: Can you tell about NCC Health Check: fs_inconsistency_check. ### Assistant: The NCC health check fs_inconsistency_check identifies CVM (Controller VM) filesystem inconsistencies by checking for EXT4-fs error/warning messages in dmesg and scanning tune2fs output for all the disks.. The NCC health check fs_inconsistency_check verifies whether any CVM (Controller VM) in the cluster is experiencing filesystem inconsistencies by checking for EXT4-fs error/warning messages in dmesg and scanning tune2fs output for all mounted disks. From NCC 4.4.0 onwards, if the failed disk causing inconsistencies is unmounted from the cluster, the check will skip the execution on the removed disk and pass.

This plugin was introduced in NCC version 3.9.3.

The check runs on CVMs on all platforms and hypervisors and is scheduled to run once every 24 hours on the prior 24 hours of data in the CVM dmesg ring buffer.

Starting with NCC-4.1.0, this check will generate the alert A3038 after 1 concurrent failure across scheduled intervals.

In NCC 4.5.0, the dependency on dmesg logs is removed. Instead, the plugin checks a system counter that gives the number of errors in real time.

Running the NCC check

The check can be run as part of a complete NCC by running:

nutanix@CVM$ ncc health_checks run_all

It can also be run individually as follows:

nutanix@CVM$ ncc health_checks run_all

You can also run the check from the Prism web console Health page. Select Actions > Run Checks > All Checks > Run.

Sample Output

For Status: PASS

nutanix@CVM$ ncc health_checks run_all

If the check results in a PASS, there are no filesystem inconsistencies detected. No action needs to be taken.

For Status: WARN

nutanix@CVM$ ncc health_checks run_all

If one or more CVMs are logging filesystem inconsistencies, the check will result in a WARN.

Note: From NCC 4.5.0, the severity is changed to FAIL. The end-user will experience "Critical" alert on the UI and "FAIL" status on the CLI when the check fails.

Output messaging

Check ID3038DescriptionCaptures EXT4-fs error messagesCauses of failureFile system inconsistencies are present on the node.ResolutionsLook for any problems in the file system. Review KB 8514.ImpactThe inability of the CVM to boot or for the upgrade pre-checks to run.Alert IDA3038Alert TitleFile system inconsistencies are detected.Alert Smart TitleFile system inconsistencies are detected on CVM: cvm_IPAlert MessageEXT4 file system errors are detected on CVM: cvm_ip: alert_msg. Investigating a WARN/CRITICAL Alert

If you see an alert for EXT filesystem errors on one or more CVMs, engage Nutanix Support.

To speed up the resolution time please collect and attach the following information to the support case:

A complete NCC report:
	nutanix@CVM$ ncc health_checks run_all
	A log bundle generated from the cluster. This can be collected through the Prism Web Console's health page. Select Actions > Collect Logs. Logs can also be collected through the command line using logbay (KB 6691 - NCC - Logbay Quickstart Guide).
	nutanix@CVM$ ncc health_checks run_all
	The output of the following commands, collected from the CVM(s) that have the EXT4 fs-error:
	nutanix@CVM$ ncc health_checks run_all
	The following command can be used to collect the needed info from all of the CVMs and should find the disk SN outputs/mount point:
	nutanix@CVM$ ncc health_checks run_all
	
 . ### Human: Now explain this as a Nutanix support agent summarizing the answer step by step. In case, you don't know the answer say - I don't know.