Copying between apfs and hfs+ external drives *extremely* slow

[JohnAtl]

You might be interested in this, which also applies to drives other than NAS drives.

Drive manufacturers are switching to SMR for NAS drives unannouced

I first saw this related to newer WD Red drives, and it appears Seagate is doing the same. Shingled Magnetic Recording (SMR) layers data when written to tracks on the drive, improving data density, but slowing the write process. This would be fine for, say, a DVR that writes once and reads multiple times. For a NAS, it means that a change in the data for a track requires rewriting the track multiple times to layer the data, thus killing throughput. For WD drives, the telltale part numbers have…