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On Wed, Oct 6, 2021 at 3:37 PM Laurence Perkins <lperkins@×××××××.net> wrote: |
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> I think what to look for there would be if there's a way to align the BTRFS chunks to the SMR blocks. |
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There are definitely ways to implement filesystems that are more |
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compatible with SMR. You basically want something like a log-based |
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filesystem. A COW filesystem is actually a really good candidate as |
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they don't do in-place writes ever, and all you need to do is defer |
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block frees and garbage collect and so on to make it more log-based. |
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One of the issues though is that these drives obfuscate how they work. |
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The filesystem has no way to intentionally write to the CMR vs SMR |
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regions. |
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This is why drive-managed SMR really shouldn't be a thing. |
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Host-managed SMR makes a LOT more sense, because then the filesystem |
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can mitigate most of the issues and not end up fighting the drive |
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firmware, whose behavior isn't even standardized. |
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> But the manufacturers decided to continue manufacturing CBR disks for the surveillance industry, so I haven't had to worry about it just yet. |
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There are lots of CMR drives out there. It is just that you have to |
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be careful as nothing is well-documented and it is all subject to |
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change. It is like trying to figure out how many channels a DIMM has |
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or what its timing capabilities are. |
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I saw a good price on an Exos drive and I believe those are all CMR. |
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This is why I use slickdeals - you can set up searches and get alerts |
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when a price drops. It also picks up stuff like Best Buy who often |
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has some of the best prices on USB enclosures for whatever reason when |
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they go on sale. |
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-- |
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Rich |
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