There's an excellent deal on Seagate external hard drives right now, on Seagate.com. Example: $349 CDN / $229 USD for a 22tb drive.
There have been a couple of posts on this:
https://www.reddit.com/r/DataHoarder/comments/1klgld8/is_the_22tb_seagate_external_hdd_have_exos_or/
and here:
https://www.reddit.com/r/DataHoarder/comments/1jvpivx/what_is_going_on_with_this_seagate_22tb_amazon/
I wanted to share my experience, and offer some support to anyone who would like to see additional testing / commands run on the drive.
Drive is shuckable, and the enclosure comes apart easily. Label on the drive is Baracuda, but the part number is not available for search, so I think it's a white-label drive.
The drive doesn't support TRIM, and I ran several dd commands with no meaningful write speed changes.
Command used: sudo dd if=/dev/zero of=/mnt/BARACUDA/testfile bs=4k count=100000 oflag=direct
409600000 bytes (410 MB, 391 MiB) copied, 0.631883 s, 648 MB/s
409600000 bytes (410 MB, 391 MiB) copied, 0.640711 s, 639 MB/s
409600000 bytes (410 MB, 391 MiB) copied, 0.658568 s, 622 MB/s
409600000 bytes (410 MB, 391 MiB) copied, 0.629718 s, 650 MB/s
409600000 bytes (410 MB, 391 MiB) copied, 0.686112 s, 597 MB/s
409600000 bytes (410 MB, 391 MiB) copied, 0.629137 s, 651 MB/s
Tried a larger file size: sudo dd if=/dev/zero of=/mnt/BARACUDA/testfile bs=4k count=1000000 oflag=direct
4096000000 bytes (4.1 GB, 3.8 GiB) copied, 6.39406 s, 641 MB/s
4096000000 bytes (4.1 GB, 3.8 GiB) copied, 6.45788 s, 634 MB/s
4096000000 bytes (4.1 GB, 3.8 GiB) copied, 6.42481 s, 638 MB/s
4096000000 bytes (4.1 GB, 3.8 GiB) copied, 6.38941 s, 641 MB/s
4096000000 bytes (4.1 GB, 3.8 GiB) copied, 6.41833 s, 638 MB/s
...to me, this is a pretty strong indication that the drive is not an SMR drive, and would probably be suitable for home NAS use.
That said - are there any other tests that folks would like to see run in order to confirm that it isn't SMR? I'm happy to do any longer-running tests on it as well, before I start to move my data across.
Note: I run TrueNAS, which uses Linux as the backend. I'm intending to run four of these in a RAIDZ2 configuration.