[LU-10784] DNE3: mkdir() automatically create remote directory on MDS which has more space

• Type: Improvement
• Resolution: Duplicate
• Priority: Minor
• Labels: dne3
• Assignee: Lai Siyao
• Reporter: Andreas Dilger

Description

On DNE system, it will be good to allow 'mkdir()' to create directory on MDT which has more free space. In this way, user doesn't need to care much about balance between MDTs. This differs from LU-10277 in that this is handled in the kernel for regular mkdir() syscalls by applications, rather than only with lfs mkdir.

Issue Links

• Clones: LU-10277 DNE3: allow 'lfs mkdir' to create directory on MDS which has more space
• duplicates: LU-13417 DNE3: mkdir() automatically create remote directory on MDS which has more space
• has to be done after: LU-10329 DNE3: REMOTE_PARENT_DIR scalability
• is related to: LU-17300 Avoid creating new dir/file/object on newly added MDT/OST
• is related to: LU-17334 Client should handle dir/file/object created on newly added MDT/OST
• is related to: LU-9309 Add ldiskfs 64-bit inode number support
• is related to: LU-15856 "lfs setdirstripe -D ... <dir>" should create directory if missing
• is related to: LU-9435 DNE2 - object placement QoS policy
• is related to: LU-13560 'lfs mkdir -i N' should be 'sticky' on a particular MDT
• is related to: LU-11213 DNE3: remote mkdir() in ROOT/ by default

Comments

[Andreas Dilger]

I think this is really the same issue as LU-13417 in the end. We need to handle space balancing for all directories, but it should be easier/default to do this at the ROOT/ directory, and less likely to happen further down the tree.

[Andreas Dilger]

As a precursor to allowing this to be done automatically across the whole filesystem, LU-11213 proposes doing it in ROOT/ and other user-specified directories is an easier entry into automatic DNE MDT balancing.