Re: [PATCH] scsi: sd: stop SSD (non-rotational) disks before reboot

From: Henrique de Moraes Holschuh
Date: Sun Jul 05 2020 - 17:45:57 EST


On Thu, 18 Jun 2020, Christoph Hellwig wrote:
> > For SSDs, I don't think an extra stop should ever be an issue.
>
> Extra shutdowns will usually cause additional P/E cycles.

I am not so sure. We're talking about enforcing clean shutdowns here
(from the SSD PoV).

A system reboot takes enough time that the SSD is likely to do about the
same amount of P cycles commiting to FLASH any important data that it
would trigger by a shutdown sequence, simply because it should not keep
important data in RAM for too long. By extension, it would not increase
E cycles either.

OTOH, unclean shutdowns *always* cause extra P/E, and that's if you're
lucky enough for it to not cause anything much worse.

--
Henrique Holschuh