Lustre stripe
Last updated
Last updated
The Lustre File System on the 5th system supports file striping, which distributes a single file across multiple OSTs (Object Storage Targets, i.e., physically distributed disks) to reduce bottlenecks and improve I/O performance. Notably, Progressive File Layout (PFL), supported since Lustre 2.10, is applied to the /scratch file system. This feature automatically adjusts the stripe count based on file size without requiring users to configure striping, thereby enhancing I/O performance. The striping settings for the Nurion file system are as follows:
Lustre maximizes I/O performance for large files by dividing data across OSTs, with the maximum effective degree of parallelism being equal to the number of OSTs. As shown in the diagram, even a single file is stored in parallel on OSTs using the Lustre Striping feature.
A command to apply striping settings to a file or directory. All files created in a directory where this command has been applied, or files generated by this command, will have the striping settings applied.
--stripe-size - Set the size of data to be stored on each OST - Once the specified size is stored, the data is saved to the next OST - The default size is 1MB, and if stripe_size is set to 0, the default value is used - stripe_size must be set as a multiple of 64KB and should be less than 4GB
--stripe-count - Set the number of OSTs to be used for striping - The default value is 1, and if stripe_count is set to 0, the default value is used. - If stripe_count is set to -1, all available OSTs will be used.
The command to check the values of the striping settings that have been applied to a file or directory.
If setstripe is specified for the directory where the model’s result files will be saved within the job script, all subsequently created subdirectories and files will inherit those settings.
Setting --stripe-count to 4 for files larger than 1GB typically improves performance. Testing is recommended when using larger values
--stripe-size is only effective for files larger than several terabytes, so using the default value is generally sufficient
