Lustre stripe
Last updated
Last updated
The Neuron Lustre File 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. In particular, the Progressive File Layout (PFL) feature, supported from Lustre 2.10 onward, is applied to the /scratch file system. This feature automatically adjusts the stripe count based on the file size, enhancing I/O performance without requiring the user to manually configure striping. The striping settings for the Neuron 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 the directory where this command has been applied, or any files created with 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 value is 1MB, and setting stripe_size to 0 uses the default
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 setting stripe_count to 0 uses the default
If stripe_count is set to -1, all available OSTs will be used
※ Command to check the striping settings applied to a file or directory
If you specify setstripe for the directory where the model’s result files will be saved within a job script, all subsequent subdirectories and files will inherit these 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
