FWIW, I've written a little tool to help incrementally, slowly, balance an array with SMR drives: https://gist.github.com/dvanders/c15d490ae380bcf4220a437b18a32f04 It balances 2 data chunks per iteration, and if that took longer than some threshold (e.g. 60s), it injects an increasingly larger sleep between subsequent iterations. I'm just getting started with DM-SMR drives in my home array (3x 8TB Seagates), but this script seems to be much more usable than a one-shot full balance, which became ultra slow and made little progress after the CMR cache filled up. And my 2 cents: the RAID1 is quite usable for my media storage use-case; outside of balancing I don't notice any slowness (and in fact it maybe quicker than usual, due to the CMR cache which sequentializes up to several gigabytes of random writes) Cheers, Dan On Sat, May 2, 2020 at 7:25 AM Rich Rauenzahn <rrauenza@xxxxxxxxx> wrote: > > Has there been any btrfs discussion off the list (I haven't seen any > SMR/shingled mails in the archive since 2016 or so) regarding the news > that WD's Red drives are actually SMR? > > I'm using these reds in my btrfs setup (which is 2-3 drives in RAID1 > configuration, not parity based RAIDs.) I had noticed that adding a > new drive took a long time, but other than than, I haven't had any > issues that I know of. They've lasted quite a long time, although I > think my NAS would be considered more of a cold storage/archival. > Photos and Videos. > > Is btrfs raid1 going to be the sweet spot on these drives? > > If I start swapping these out -- is there a recommended low power > drive? I'd buy the red pro's, but they spin faster and produce more > heat and noise. > > Rich
