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HDD: Any quality difference between portable and plugged in external HDD? (lemmy.org)
submitted 7 months ago by to c/piracy@lemmy.dbzer0.com
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I am debating between those Western Digital portable drives that go up to 5tb that function with USB only (WD my passport) and the bigger ones (eg my book) that are bigger and need power outlet besides the USB connection.

Is there any difference in quality or durability to store media?

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[–] 3 points 7 months ago (5 children)

Some WD red drives (particularly under 16TB) are SMR. There was a whole scandal with this and you can look up a list. WD Red Pro are always CMR and I think the plus typically are too but you can easily search up a list of SMR models.

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  • [–] 1 point 7 months ago (4 children)

    So CMR superior to SMR?

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  • [–] 2 points 6 months ago* (2 children)

    CMR performs better under all workload types.

    Shingled Magnetic Recording overlays the tracks on top of each other like roof shingles. This means you can fit more tracks on the same platter which means you can fit more data. Unfortunately this also means whenever writing data you have to rewrite tracks adjacent to the track you're rewriting which leads to a lot of reshuffling of data which leads to very slow writes when this is taking place (say you edit a file or replace it, delete some and copy over others).

    SMR allows more storage for less money but it takes a serious performance hit (right now about the largest CMR disks you can get as an example are about 28TB in size, by contrast you can get 40TB SMR disks so it can significantly amplify storage). It shouldn't be used for many scenarios. For archival backup it's fine. For disks that are having data changed on them anywhere near regularly it's not great.

    I want to underline that for USB powered portable 5200RPM disks they're already slower disks when CMR, so as SMR they get a lot slower in write performance (one I had would drop down to sustained low 20MB/s write speeds when over 60% full). A 7200RPM SMR disk with proper 12V power from a PSU rail or an AC adapter would likely be double that at worst by contrast.

    So SMR has its uses, it has its place. It's just a lot of people who don't know might use it in places where CMR is more appropriate and would give them a better experience. So by all means if you're using SMR in back-up disks to your primary ones to create back-up snapshots that are updated infrequently continue to do so, they're fine for that especially if the tasks are done on machines that can be left running for days while the data is slowly written.

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  • [–] 1 point 6 months ago

    I give you a paintbrush. I want you paint a rectangle. With CMR, the brush can paint stripes as wide as the itself. Simple, fast, reliable, but you can only fit so many stripes in that rectangle.

    Enter SMR. With SMR, you can paint smaller stripes and fit more of them in the rectangle with the same sized bush by painting over your old stripes. You cover part of it up with the next pass but enough of the old stripe is left exposed you can still see what’s there.

    But there’s a problem. What if something changes? Now you go back and paint again and it overwrites multiple stripes, so you have to cover that up again on the next line, which means you have to just keep going down the line, trying to fix the damage from the changed line above it. The drives firmware can handle that by itself just fine but now that simple change means the drive has a lot more work to do.

    If you need to write once, change never, read many, SMR is fine. For literally anything else, it’s worthless.

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