Messages in this thread | | | Subject | Re: [PATCH 01/21] block: Add atomic write operations to request_queue limits | From | "Martin K. Petersen" <> | Date | Wed, 04 Oct 2023 14:26:42 -0400 |
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Bart,
> In my opinion there is a contradiction between the above reply and > patch 19/21 of this series. Data written with the SCSI WRITE ATOMIC > command is not guaranteed to survive a power failure.
That is not the intent. The intent is to ensure that for any given application block (say 16KB), the application block on media will contain either 100% old data or 100% new data. Always.
If a storage device offers no such guarantee across a power failure, then it is not suitable for use by applications which do not tolerate torn writes. That is why the writes-are-atomic-unless-there's-a-problem variant of the values reports in NVMe are of no interest.
-- Martin K. Petersen Oracle Linux Engineering
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