Re: [gentoo-user] Seagate hard drives with dual actuators.

[Rich Freeman <rich0@gentoo.org>]

On Fri, Nov 15, 2024 at 10:35 AM Michael <confabulate@kintzios.com> wrote:
>
> Host managed SMRs (HM-SMR) require the OS and FS to be aware of the need for
> sequential writes and manage submitted data sympathetically to this limitation
> of the SMR drive, by queuing up random writes in batches and submitting these
> as a sequential stream.
>
> I understand the ext4-lazy option and some patches on btrfs have improved
> performance of these filesystems on SMR drivers, but perhaps f2fs will perform
> better?  :-/

IMO a host-managed solution is likely to be the only thing that will
work reliably.  If the drive supports discard/trim MAYBE a dumber
drive might be able to be used with the right filesystem.  Even if
you're doing "write-once" workloads any kind of metadata change is
going to cause random writes unless the filesystem was designed for
SMR.  Ideally you'd store metadata on a non-SMR device, though it
isn't strictly necessary with a log-based approach.

If the SMR drive tries really hard to not look like an SMR drive and
doesn't support discard/trim then even an SMR-aware solution probably
won't be able to use it effectively.  The drive is going to keep doing
read-before-write cycles to preserve data even if there is nothing
useful to preserve.

--
Rich