MMFS_LONGDISKIO

This topic describes the MMFS_LONGDISKIO error log available in IBM Spectrum Scale™.

The MMFS_LONGDISKIO error log entry indicates that GPFS™ is experiencing very long response time for disk requests. This is a warning message and can indicate that your disk system is overloaded or that a failing disk is requiring many I/O retries. Follow your operating system's instructions for monitoring the performance of your I/O subsystem on this node and on any disk server nodes that might be involved. The data portion of this error record specifies the disk involved. There might be related error log entries from the disk subsystems that will pinpoint the actual cause of the problem. If the disk is attached to an AIX® node, refer to AIX in IBM® Knowledge Center and search for performance management. To enable or disable, use the mmchfs -w command. For more details, contact the IBM Support Center.

The mmpmon command can be used to analyze I/O performance on a per-node basis. For more information, see Monitoring GPFS I/O performance with the mmpmon command and Failures using the mmpmon command.