[LU-16938] "lfs setstripe -C -1" stripes too widely, should be limited to OST_COUNT

• Type: Improvement
• Resolution: Fixed
• Priority: Major
• Fix Version/s: Lustre 2.16.0
• Affects Version/s: Lustre 2.15.0
• Severity: 3
• Assignee: Rajeev Mishra
• Reporter: Rajeev Mishra

Description

I am reaching out to seek clarification regarding the expected behavior of the "lfs setstripe" command when using the -C -1 option.

Currently, it appears that this command is creating a higher stripe count than anticipated. For instance, on my test system, it generated a stripe count of 2727 for a single file. This count exceeds the allowed limit of LOV_MAX_STRIPE_COUNT. 

I am uncertain about the appropriate solution to address this issue related to the "-1" argument. I have contemplated the following options:

1.    Consider making the option -1 illegal, preventing its usage altogether.

2.    Implement a mechanism to automatically set the stripe count to the maximum allowed value (LOV_MAX_STRIPE_COUNT) if the count exceeds this limit.

I would greatly appreciate your input and guidance in this matter. It is worth noting that setting the stripe count higher than LOV_MAX_STRIPE_COUNT leads to other problems, such as the failure of the "llapi_layout_get_by_fd" API to open the file.

Please let me know your input.

Issue Links

• is related to: LU-17925 sanity-flr test_0b: lfs mirror create: cannot create composite file: Numerical result out of range
• is related to: LU-17199 'lfs setstripe -C -1' can be set beyond overstripe count > 2000
• is related to: LU-18244 add 'lfs mkdir -C -N' overstriping support
• is related to: LU-16623 lod_statfs_and_check() does not skip unusable OSTs
• is related to: LU-13748 'lfs setstripe -C -1' stripes too widely

Comments

[Peter Jones]

Seems like we are going to fix in place with LU-17925 rather than revert

[Gerrit Updater]

"Andreas Dilger <[e-mail]>" uploaded a new patch: https://review.whamcloud.com/c/fs/lustre-release/+/55543
Subject: LU-16938 revert: utils: setstripe overstripe multiple OST count"
Project: fs/lustre-release
Branch: master
Current Patch Set: 1
Commit: 964f07f84eb67f221793a3deb7954a46d1157255

[Peter Jones]

Given that this is an enhancement and not time-sensitive and we are trying to finalize the 2.16 release ATM, let's please have a revert patch ready as a contingency...

[Andreas Dilger]

This is broken due to storing the negative stripe count as "stripe_count - 32" instead of just "-stripe_count" and needs to be fixed before 2.16.0 is released.

[Peter Jones]

Merged for 2.16

[Gerrit Updater]

"Oleg Drokin <[e-mail]>" merged in patch https://review.whamcloud.com/c/fs/lustre-release/+/54192/
Subject: LU-16938 utils: setstripe overstripe multiple OST count
Project: fs/lustre-release
Branch: master
Current Patch Set:
Commit: 1a6ef725c285dd5c25c976956ba754dc470f6c1c