WB My Book 6TB - SMR?


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  • 2 years later...

Only for those who are interested how to verify SMR.

 

The easiest way is to check the CDM benchmark. In the above example the benchmark resulted >10 MB/s for random writes. This is - as of today - impossible for CMR drives, so it must be a SMR. Compare the results with SMR benchmarks here (the fastest SMR drive reached 5 MB/s, which fits to the 250 MB/s for sequential writes):

https://www.hardwareluxx.de/index.php/artikel/hardware/storage/49350-sieben-6-tb-festplatten-verschiedener-hersteller-im-test.html?start=10

 

Another method is to set more cycles in CDM and after it wrote multiple times the 4K random writes, copy the benchmark file that was generated on the disk through CDM to an external target. Now you can interrupt CDM (which usually deletes this file) and by that only a sequential copy transfer is running and if it is an SMR drive, it will be super slow (< 20 MB/s) as it needs to jump between media cache tracks (4K writes are cached here) and usual data tracks.

 

By hearing or measuring the power consumption, there is even a third method. Wait for the multiple 4K random writes, copy the benchmark file and close CDM. Stop the copy transfer and directly after that the drive starts to clean the Media Cache, which is clearly audible (like a white noise). Power Consumption Example:

image.png.9d12c475e6e7e924fb9a247b31fedca0.png

 

This is why the power consumption of SMR drives is much higher than expected.

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