Details
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Bug
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Resolution: Fixed
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Major
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None
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Lustre 2.14.0
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None
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3
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9223372036854775807
Description
This issue was created by maloo for Lai Siyao <lai.siyao@whamcloud.com>
This issue relates to the following test suite run: https://testing.whamcloud.com/test_sets/ddd8bcd4-cb29-447c-8d67-c749d3fc38f1
Attachments
Issue Links
- is related to
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LU-12506 Client unable to mount filesystem with very large number of MDTs
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- Resolved
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This may need to be replaced again with the "all_char" hash instead of "fnv_1a_64" since there are still errors when running on a large number of MDTs (e.g. 20+). The hash function is not perfectly uniform, only statistically so, which results in MDT imbalances when the stripe count is higher (e.g. from my 12-MDT test run for v6 of patch https://review.whamcloud.com/38058 "
LU-12506tests: clean up MDT name generation":https://testing.whamcloud.com/test_sets/1e911540-e60d-4086-bba6-fa975354cb9d
The "all_chars" hash is perfectly uniform (essentially round-robin) as long as the filenames are generated in a uniform pattern (e.g. counter).