The file system /scratch on Setonix is a Lustre filesystem that makes use of file striping to increase I/O performance and is performed automatically. This means that files are automatically divided into chunks that are written or read simultaneously across a set of Object Storage Targets (OSTs). In previous systems, users were recommended to use optimal file striping settings depending on the size of the different files read/written by their applications but, thanks to the Progressive File Layout (PFL) technology, that is not longer needed in our current Lustre installations.
PFL automatically enforces different striping settings for different segments of the files as they grow, allowing great I/O performance for most of the applications without the need for users to "optimise" their own striping settings. Because of this, we ask users not to manually adjust the file striping. If users feel the default PFL settings are not meeting their needs, please contact raise a ticket to the helpdesk.
/scratch now uses Progressive FIle Layout
By default, Setonix /scratch use PFL to stripe files to make best use of the SSD and HDD. This default settings has been set to work for almost all workflows and we recommend not setting the stripping explicitly.