[LU-8998] Progressive File Layout (PFL)

Related — Wed, 22 Nov 2017 03:54:33 +0000

The work tracked under this ticket will implement Progressive File Layouts (PFL).

This feature simplifies Lustre usage of large files, avoiding the need for users to predetermine the required layout for each file. The goal is that a single file layout specified at file creation time can balance the following conflicting needs:

minimize the number of stripes for small files to avoid the overhead of creating and accessing multiple OST objects
maximize the number of stripes for large files to utilize the available bandwidth as well as distribute space usage to avoid consuming all of the space on a single OST
flexibility to specify a layout that is suitable for a majority of uses, while allowing for variability and flexibility between users, applications, and sites

The administrator will be able to set a specific progressive layout for new files created in the filesystem, and users will be able to specify progressive layouts on their own files for their specific needs. It should be possible to specify a default progressive layout template for a directory that is inherited by new files and directories created in that directory, as well as a filesystem-wide global default layout that is used in the absence of more specific layouts.

Whamcloud Community JIRA

[LU-8998] Progressive File Layout (PFL)