I’m looking for non-shingled spinning 2.5" SATA drives

  • due to data storage policies, it must NOT be a SSD but a spinning drive
  • due to the use of ZFS, it can’t be a SMR
  • 1Tb or more (2Tb would be nice)
  • ideally 9.5 mm or thinner (7mm would be preferred for a better airflow, 15 mm would require a 3d-printed cover)
  • ideally new (new-old stock and used drives would require a few days of testing to validate the SMART info and the absence of bad sectors)

I’ve heard the WD Blue 2.5" and the Seagate Exos might be valid options:

If you know about other options, could you please list them?

  • Far_Marsupial6303B
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    11 months ago

    There’s a bit of mystery around these drives.

    TL;DR: It’s extremely hit and miss on which of these drives had (if ever) CMR/PMR platters. There seems to have been a time in the mid-2010s when Seagate was using Samsung technology in some of their drives. So finding which drives definitely did (if ever) had CMR/PMR platters is extremely difficult.

    The Hard Drive Platter Database says the ST4000LM024 and ST5000LM000 are SMR.

    BarraCuda (5526RPM, 128MB cache, SATA-600 interface, Advanced Format, Shingled Magnetic Recording, 15mm z-height)

    ST4000LM024 4TB (4/8)*

    ST5000LM000 5TB (5/10)

    *Note: The manual suggests there may be 10-headed versions of this model floating around.

    https://rml527.blogspot.com/2010/09/hdd-platter-database-seagate-25.html

    And so does the the Seagate Datasheet dated May 2020

    https://www.seagate.com/content/dam/seagate/migrated-assets/www-content/datasheets/pdfs/barracuda-2-5-DS1907-3-2005US-en_US.pdf

    However, their Sep 2020 product manual says Perpendicular. Page 10

    In addition, the blog states the ST4000LM016 uses 800GB platters.

    800GB/platter Section (all drives under here use platters that can hold 800GB of data apiece.)

    SpinPoint M10P / Seagate Laptop HDD (5400RPM, 128MB cache, SATA-600 interface, Advanced Format, Shingled Magnetic Recording, 15mm z-height)

    ST3000LM016 3TB (4/8 [short-stroked])

    ST4000LM016 4TB (5/10)

    Note: The product manual lists multiple M/Ns per capacity, and isn’t forthcoming on the differences (besides encryption); only the “016” models, which appear the most common, are listed. Drive-managed SMR use in at least the ST4000LM016 (though I wouldn’t expect “shingles or not” to be a differentiating factor between the model numbers) is highly likely, given the eerily strong performance of randomized 4K writes in CrystalDiskMark 1000MB (a consistent behaviour of SMR HDDs across manufacturers), along with talk in data recovery forums of a “media cache”.

    Note 2: As with the D8Xes and M9T(U)s, these came out sometime after the Seagate buyout, and the Samsung branding on the labels is fully replaced by Seagate’s in later batches.

    https://rml527.blogspot.com/2010/09/hdd-platter-database-samsung-25.html

    So while as a stretch it’s possible an 800GB CMR platter existed, since it’s ~17% more data than 667GB, it’s extremely unlikely a ~35% increase to 1TB CMR could have been achieved.

    What may be the answer is from this 2016 review:

    All the new BarraCuda 2.5” HDDs feature 128 MB of DRAM cache as well as multi-tier caching (MTC) technology, which is designed to hide peculiarities of SMR. Hard drives featuring shingled recording write new magnetic tracks that overlap part of the previously written tracks. This may slow down the writing process since the architecture requires HDDs to rewrite adjacent tracks after any writing operation. To “conceal” such peculiarities, Seagate does a number of tricks. Firstly, it organizes SMR tracks into bands in a bid to limit the amount of overwriting. Secondly, the MTC technology uses several bands of PMR tracks on the platters, around 1 GB of NAND flash cache as well as DRAM cache. When workloads generate relatively small amount of writes, the HDD writes data to NAND and/or to the PMR tracks at a predictable data rate. Then, during light workloads or idle time, the HDD transfers written data from the caches to SMR tracks, as described by Mark Re (CTO of Seagate) earlier this year.

    https://www.anandtech.com/show/10757/seagate-introduces-barracuda-25-mobile-hard-drives-with-up-to-5-tb-capacity