updatedb considerations

On some Linux® distributions, the system is configured by default to run the file system indexing utility updatedb through the cron daemon on a periodic basis (usually daily).

This utility traverses the file hierarchy and generates a large I/O load. For this reason, it is configured by default to skip certain file system types and nonessential file systems. However, the default configuration does not prevent updatedb from traversing GPFS file systems. In a cluster this results in multiple instances of updatedb traversing the same GPFS file system simultaneously. This causes general file system activity and lock contention in proportion to the number of nodes in the cluster. On smaller clusters, this may result in a relatively short-lived spike of activity, while on larger clusters, depending on the overall system throughput capability, the period of heavy load may last longer. Usually the file system manager node will be the busiest, and GPFS would appear sluggish on all nodes. Re-configuring the system to either make updatedb skip all GPFS file systems or only index GPFS files on one node in the cluster is necessary to avoid this problem.