2021-11-30 15:00:48 +00:00
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Auto-repair on read
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===================
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2024-10-23 09:49:47 +00:00
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If data or metadata that are found to be damaged at the time they’re read from a device,
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for example because the checksum does not match, they can be salvaged if the filesystem
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has another valid copy. This can be achieved by using a block group profile with redundancy
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like DUP, RAID1-like, or RAID5/6.
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The correct data is returned to the user application and the damaged copy is replaced by it.
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When this happens, a message is emitted to the system log.
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If there are multiple copies of data and one of them is damaged but not read by the user
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application, then this is not detected.
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To ensure the verification and automatic repair of all data and metadata copies, the
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:doc:`scrub<Scrub>` operation must be initiated manually.
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