[LU-8616] DNE3: enhance "lfs mkdir" to select specific MDTs

• Type: New Feature
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.11.0, Lustre 2.12.0
• Labels: dne3
• Assignee: Lai Siyao
• Reporter: Adam Roe (Inactive)

Description

Request to enhance the functionality of "lfs setdirstripe" to include the selection of specific MDT's as appose to a series.

The current implementation allows for stripe on a series of MDT's, e.g.:

lfs setdirstripe -D -i 0 -c 4 /some/dir

This will stripe to 4 MDT's at the start index of MDT0.

I am proposing we enhance this to stripe to multiple specific MDT's, e.g.:

lfs setdirstripe -D -o 1,3,5,7 /some/dir

This will stripe to 4 specific MDT's with the indexes 1, 3, 5 & 7 - in which case no start index would be required.

This will allow for more controllable striping in a case where a file system could have many MDT's across many systems and in cases where multiple MDT's may exist on one server.

Issue Links

• is cloned by: LU-15494 DNE3: "lfs setdirstripe -D" for specific MDTs
• is related to: LU-10766 Incorrect freeing in llapi_dir_create
• is related to: LU-7827 DNE3: automatically select MDT for lfs mkdir
• is related to: LU-11571 MDT pool
• is related to: LU-9392 lfs migrate -o and lfs setstripe -o should pick OST from ost_list