Western Digital recently announced new data center HDDs that increase Shingled Magnetic Recording (SMR) capacity to 32TB and Conventional Magnetic Recording (CMR) capacity to 26TB. The company...
You’ve made me uncertain if I’ve somehow never noticed this before, so I gave it a shot. I’ve been dd-ing /dev/random onto one of those drives for the last 20 minutes and the transfer rate has only dropped by about 4MB/s since I started, which is about the kind of slowdown I would expect as the drive head gets closer to the center of the platter.
EDIT: I’ve now been doing 1.2GB/s onto an 8 drive RAID0 (8x 600GB 15k SAS Seagates) for over 10 minutes with no noticable slowdown. That comes out to 150MB/s per drive, and these drives are from 2014 or 2015. If you’re only getting 60MB/s on a modern non-SMR HDD, especially something as dense as an 18TB drive, you’ve either configured something wrong or your hardware is broken.
When the cache isn’t full, yes, that’s true. Copy a file that’s significantly bigger than cache and performance will drop part way through.
You’ve made me uncertain if I’ve somehow never noticed this before, so I gave it a shot. I’ve been
dd-ing/dev/randomonto one of those drives for the last 20 minutes and the transfer rate has only dropped by about 4MB/s since I started, which is about the kind of slowdown I would expect as the drive head gets closer to the center of the platter.EDIT: I’ve now been doing 1.2GB/s onto an 8 drive RAID0 (8x 600GB 15k SAS Seagates) for over 10 minutes with no noticable slowdown. That comes out to 150MB/s per drive, and these drives are from 2014 or 2015. If you’re only getting 60MB/s on a modern non-SMR HDD, especially something as dense as an 18TB drive, you’ve either configured something wrong or your hardware is broken.