[LU-16227] "lfs setdirstripe -D -i x,y,x" should not create a default striped directory layout

Related — Mon, 1 May 2023 00:19:23 +0000

Users have repeatedly used "lfs setdirstripe -D -i x,y,z <directory>" with the mistaken belief that this will load balance or round-robin subdirectory creation among the x,y,z MDTs. That is not the case, and instead this will cause all new subdirectories to be striped across all of the specified MDTs, which is a terrible idea and can lead to filesystem problems if too many striped directories are created (too large REMOTE_PARENT_DIR, slow performance, running out of inodes, etc).

The use of "-i x,y,z" should return a clear error that this is creating a default striped directory layout and that this is a bad idea, if it is not accompanied by "-c N" that matches the number of index values given. That makes it more clear that this command is creating an N-striped directory instead of leading users in the wrong direction.

Whamcloud Community JIRA

[LU-16227] "lfs setdirstripe -D -i x,y,x" should not create a default striped directory layout