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Western Digital Continues Working On SMR / Zoned Device Support For Btrfs

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  • #21
    Originally posted by Adarion View Post
    Either way, SMR _is_ slow as soon as you have to re-write overlapping sectors.
    (As is also the case with Flash media. You can only write an erased sector, and you can only erase a whole erase-block at a time)

    Anyway, log-structured filesystems (F2FS, UDF, etc.) and CoW filesystems (BTRFS, ZFS, BcacheFS) are, by design over-writing a lot less in place.
    (Some like UDF have even alternate mode for media that CANNOT physically be overwritten, like DVD-R media)

    I'm sure that SUSE guys will manage to successfully tune BTRFS for that.
    (prefer appending data to a not-yet-full chunk over filling an old half-erased chunking ; try to garbage collect older half erased chunk and auto-balance them)