IntegrityScan, another component of the OneFS job engine, is responsible for examining the entire file system for inconsistencies. It does this by systematically reading every block and verifying its associated checksum. Unlike traditional ‘fsck’ style file system integrity checking tools, IntegrityScan is designed to run while the cluster is fully operational, thereby removing the need for any downtime. If IntegrityScan detects a checksum mismatch, a system alert is generated and written to the syslog and OneFS automatically attempts to repair the suspect block.
The IntegrityScan phase is run manually if the integrity of the file system is ever in doubt. Although this process may take several days to complete, the file system is online and completely available during this time. Additionally, like all phases of the OneFS job engine, IntegrityScan can be prioritized, paused, or stopped, depending on the impact to cluster operations.