Details
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Improvement
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Resolution: Not a Bug
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Minor
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None
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Lustre 2.12.6
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None
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3
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9223372036854775807
Description
When a file is mirrored and the mirrored is broken file time stamps should be preserved. Here we see that ctime and mtime change to the mirror creation time.
Initial File:
# stat testfile
File: 'testfile'
Size: 59535 Blocks: 120 IO Block: 4194304 regular file
Device: 521e79ech/1377729004d Inode: 342273918398214817 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2022-02-14 15:48:45.000000000 -0800
Modify: 2022-02-14 15:48:45.000000000 -0800
Change: 2022-02-14 15:48:45.000000000 -0800
Now we mirror
# date; lfs mirror extend -N S 1M -c 1 -p hdd-pool testfile Mon Feb 14 15:50:27 PST 2022
State the File and layout
# stat testfile
File: 'testfile'
Size: 59535 Blocks: 120 IO Block: 4194304 regular file
Device: 521e79ech/1377729004d Inode: 342273918398214817 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2022-02-14 15:48:45.000000000 -0800
Modify: 2022-02-14 15:48:45.000000000 -0800
Change: 2022-02-14 15:48:45.000000000 -0800
Birth: -
pfe25 /nobackupp18/mhanafi # lfs getstripe testfile
testfile
lcm_layout_gen: 1
lcm_mirror_count: 2
lcm_entry_count: 4
lcme_id: 65537
lcme_mirror_id: 1
lcme_flags: init,prefer
lcme_extent.e_start: 0
lcme_extent.e_end: 268435456
lmm_stripe_count: 1
lmm_stripe_size: 16777216
lmm_pattern: raid0
lmm_layout_gen: 0
lmm_stripe_offset: 109
lmm_pool: ssd-pool
lmm_objects:
- 0: { l_ost_idx: 109, l_fid: [0x90000040a:0x53990:0x0] }
lcme_id: 65538
lcme_mirror_id: 1
lcme_flags: prefer
lcme_extent.e_start: 268435456
lcme_extent.e_end: 5368709120
lmm_stripe_count: -1
lmm_stripe_size: 16777216
lmm_pattern: raid0
lmm_layout_gen: 0
lmm_stripe_offset: -1
lmm_pool: ssd-pool
lcme_id: 65539
lcme_mirror_id: 1
lcme_flags: 0
lcme_extent.e_start: 5368709120
lcme_extent.e_end: EOF
lmm_stripe_count: 16
lmm_stripe_size: 16777216
lmm_pattern: raid0
lmm_layout_gen: 0
lmm_stripe_offset: -1
lmm_pool: hdd-pool
lcme_id: 131073
lcme_mirror_id: 2
lcme_flags: init
lcme_extent.e_start: 0
lcme_extent.e_end: EOF
lmm_stripe_count: 1
lmm_stripe_size: 1048576
lmm_pattern: raid0
lmm_layout_gen: 0
lmm_stripe_offset: 0
lmm_pool: hdd-pool
lmm_objects:
- 0: { l_ost_idx: 0, l_fid: [0x2c0000409:0x30c3e:0x0] }
Break the mirror and stat the file. File ctime and atime has changed.
date; lfs mirror split -d --mirror-id 1 testfile Mon Feb 14 15:51:31 PST 2022
# stat testfile
File: 'testfile'
Size: 59535 Blocks: 120 IO Block: 4194304 regular file
Device: 521e79ech/1377729004d Inode: 342273918398214817 Links: 1
Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
Access: 2022-02-14 15:50:27.000000000 -0800
Modify: 2022-02-14 15:48:45.000000000 -0800
Change: 2022-02-14 15:50:27.000000000 -0800
Birth: -
Attachments
Issue Links
- is duplicated by
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LU-14508 lfs mirror operations do not preserve timestamps
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- Resolved
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Activity
Hi mhanafi,
We're still discussing this, because the blocks change on disk, ctime should change (according to POSIX standard), this is expected behavior, (if the blocks don't change, this patch will prevent ctime updates).
Because of this we need to discuss how to deliver this with (possibly) a configuration option to turn on and off this behavior.
-cf
Generally mirror split will change the block count and therefore should update the ctime. Do you have some workflow or application that is affected by the ctime update?
Hi mhanafi after some discussion with the developers, this behavior is as designed specifically desirable with the creation of new mirrors.