[LU-15565] lfs getstripe --yaml should use an array for components

• Status: Open
• Project: Lustre
• Type: Bug
• Priority: Minor
• Reporter: John Hammond
• Assignee: WC Triage
• Resolution: Unresolved
• Severity: 3

Description

For composite files lfs getstripe --yaml uses a key for each component rather than an array:

$ lfs getstripe --yaml f0
  lcm_layout_gen:    1
  lcm_mirror_count:  2
  lcm_entry_count:   2
  component0:
    lcme_id:             65537
    lcme_mirror_id:      1
    lcme_flags:          init
    lcme_extent.e_start: 0
    lcme_extent.e_end:   EOF
    sub_layout:
      lmm_stripe_count:  1
      lmm_stripe_size:   1048576
      lmm_pattern:       raid0
      lmm_layout_gen:    0
      lmm_stripe_offset: 2
      lmm_objects:
      - l_ost_idx: 2
        l_fid:     0x100020000:0xd1:0x0

  component1:
    lcme_id:             131073
    lcme_mirror_id:      2
    lcme_flags:          init
    lcme_extent.e_start: 0
    lcme_extent.e_end:   EOF
    sub_layout:
      lmm_stripe_count:  1
      lmm_stripe_size:   1048576
      lmm_pattern:       raid0
      lmm_layout_gen:    0
      lmm_stripe_offset: 3
      lmm_objects:
      - l_ost_idx: 3
        l_fid:     0x100030000:0xd1:0x0

Using "components

{0...}

" instead of any array is poor YAML style and hinders the use of the output with common YAML tooling. If an array ("components") was used instead of numbered keys then we could do things like:

lfs getstripe --yaml f0 | yq '.components[] | select(.lcme_flags == "init,stale")'

Issue Links

• is related to: LU-5170 lfs usability
• is related to: LU-14156 mirror split to check for last in-syn...

Comments

[John Hammond]

adilger what do you think about changing this to be more yaml correct?

[Andreas Dilger]

I don't think there was a particular reason for the current format being used. What would the new format look like?

The main concern would be compatibility with existing YAML parsers, as well as any regression tests that depend on the current format (not sure if those exist), but if you say that the current format is not very YAML-friendly, then that is probably not likely to be an issue.

[John Hammond]

$ lfs getstripe --yaml f0
  lcm_layout_gen:    1
  lcm_mirror_count:  2
  lcm_entry_count:   2
  components:
  - lcme_id:             65537
    lcme_mirror_id:      1
    lcme_flags:          init
    lcme_extent.e_start: 0
    lcme_extent.e_end:   EOF
    sub_layout:
      lmm_stripe_count:  1
      lmm_stripe_size:   1048576
      lmm_pattern:       raid0
      lmm_layout_gen:    0
      lmm_stripe_offset: 2
      lmm_objects:
      - l_ost_idx: 2
        l_fid:     0x100020000:0xd1:0x0
  - lcme_id:             131073
    lcme_mirror_id:      2
    lcme_flags:          init
    lcme_extent.e_start: 0
    lcme_extent.e_end:   EOF
    sub_layout:
      lmm_stripe_count:  1
      lmm_stripe_size:   1048576
      lmm_pattern:       raid0
      lmm_layout_gen:    0
      lmm_stripe_offset: 3
      lmm_objects:
      - l_ost_idx: 3
        l_fid:     0x100030000:0xd1:0x0

[Andreas Dilger]

Looks reasonable.