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    • New Feature
    • Resolution: Fixed
    • Blocker
    • Lustre 2.13.0 Manual
    • None
    • None
    • 9223372036854775807

    Description

      Documentation needed for LU-11213 DNE work

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            [LUDOC-442] Documentation needed for LU-11213 DNE work

            Joseph Gmitter (jgmitter@whamcloud.com) merged in patch https://review.whamcloud.com/36615/
            Subject: LUDOC-442 dne: directory creation by space/inode
            Project: doc/manual
            Branch: master
            Current Patch Set:
            Commit: ccce8bbf109d3531df7ae5b6c65af04e9b48a757

            gerrit Gerrit Updater added a comment - Joseph Gmitter (jgmitter@whamcloud.com) merged in patch https://review.whamcloud.com/36615/ Subject: LUDOC-442 dne: directory creation by space/inode Project: doc/manual Branch: master Current Patch Set: Commit: ccce8bbf109d3531df7ae5b6c65af04e9b48a757

            Joseph Gmitter (jgmitter@whamcloud.com) uploaded a new patch: https://review.whamcloud.com/36615
            Subject: LUDOC-442 dne: directory creation by space/inode
            Project: doc/manual
            Branch: master
            Current Patch Set: 1
            Commit: f15a832c2ea297df514ff54326fcfcd03237c33e

            gerrit Gerrit Updater added a comment - Joseph Gmitter (jgmitter@whamcloud.com) uploaded a new patch: https://review.whamcloud.com/36615 Subject: LUDOC-442 dne: directory creation by space/inode Project: doc/manual Branch: master Current Patch Set: 1 Commit: f15a832c2ea297df514ff54326fcfcd03237c33e
            laisiyao Lai Siyao added a comment -

            Maybe not in a new section, we can add this in section "13.10. Creating a directory striped across multiple MDTs", explain the effect of argument '-mdt-index' and '-mdt-hash' of command 'lfs setdirstripe', and also explain default directory layout here.

            laisiyao Lai Siyao added a comment - Maybe not in a new section, we can add this in section "13.10. Creating a directory striped across multiple MDTs", explain the effect of argument '- mdt-index' and ' -mdt-hash' of command 'lfs setdirstripe', and also explain default directory layout here.

            OK, so you are proposing that we create a new section/chapter this and include the changes in LU-12624 for that work. What area of the manual should we insert this section?

            jgmitter Joseph Gmitter (Inactive) added a comment - OK, so you are proposing that we create a new section/chapter this and include the changes in LU-12624 for that work. What area of the manual should we insert this section?
            laisiyao Lai Siyao added a comment -

            As we talked before, there doesn't exist a chapter for directory creation, so even the original interface introduced by LU-11213 is changed by LU-12624: 'space' hash type is removed, and now 'lfs setdirstripe -D -I -1' will produce the same effect, that means, if the starting MDT offset is '-1', the directory will be created by MDT space/inode usage.

            Note that the patch for LU-12624 https://review.whamcloud.com/#/c/35825/ is not landed yet.

            laisiyao Lai Siyao added a comment - As we talked before, there doesn't exist a chapter for directory creation, so even the original interface introduced by LU-11213 is changed by LU-12624 : 'space' hash type is removed, and now 'lfs setdirstripe -D -I -1' will produce the same effect, that means, if the starting MDT offset is '-1', the directory will be created by MDT space/inode usage. Note that the patch for LU-12624 https://review.whamcloud.com/#/c/35825/ is not landed yet.

            laisiyao: I know we spoke about this quite some time ago, but can you look at the latest copy of the manual and suggest where exactly that we should insert the above text? Is anything more needed to add?

            jgmitter Joseph Gmitter (Inactive) added a comment - laisiyao : I know we spoke about this quite some time ago, but can you look at the latest copy of the manual and suggest where exactly that we should insert the above text? Is anything more needed to add?

            Lai once stated the following, which needs to be expanded upon for the manual:

            A new hash type "space" is added to balance MDT space usage, once a default directory stripe is set on a plain directory, e.g.
            lfs setdirstripe -D -i -1 -H space <dir1>

            The subsequent syscall "mkdir" (NB, not "lfs mkdir ...") under <dir1> will choose a MDT with balanced space usage, the policy is:

            • if free inodes/blocks on all MDT are almost the same, choose MDT roundrobin.
            • otherwise create more subdirectories on MDTs with more free inodes/blocks.
            jgmitter Joseph Gmitter (Inactive) added a comment - Lai once stated the following, which needs to be expanded upon for the manual: A new hash type "space" is added to balance MDT space usage, once a default directory stripe is set on a plain directory, e.g. lfs setdirstripe -D -i -1 -H space <dir1> The subsequent syscall "mkdir" (NB, not "lfs mkdir ...") under <dir1> will choose a MDT with balanced space usage, the policy is: if free inodes/blocks on all MDT are almost the same, choose MDT roundrobin. otherwise create more subdirectories on MDTs with more free inodes/blocks.

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              laisiyao Lai Siyao
              jgmitter Joseph Gmitter (Inactive)
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                Updated:
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