Suboptimal performance due to low values assigned to IBM Storage Scale configuration parameters

Most GPFS configuration parameters have default values. For example, the pagepool attribute defaults to either one-third of the physical memory on the node or 1 GiB (whichever is smaller), maxMBpS defaults to 2048 and maxFilesToCache defaults to 4000. However, if the IBM Storage Scale configuration parameters are explicitly set to values lower than their default values by the user, it can impact the I/O performance.

Problem identification

On the GPFS node, issue the mmdiag --config command to display and verify the values of the GPFS configuration parameters. Check whether these values match the optimal values set for IBM Storage Scale system configuration. For more information on optimal values for configuration parameter see Tuning Parameters.

Problem resolution and verification

Issue the mmchconfig Attribute=value -i command to set the configuration parameters to their optimal values based on the best practices followed for an IBM Storage Scale system configuration.

You might need to restart GPFS for certain configuration parameter values to take effect. Issue the mmshutdown command, followed by the mmstartup command to restart GPFS. Issue the mmdiag --config command to verify the configuration changes and updates.