[Info-vax] Do any disks still lie about writing data to permanent storage ?

[Simon Clubley]

On 2021-07-06, <kemain.nospam at gmail.com> <kemain.nospam at gmail.com> wrote:
>
> As Jan-Erik correctly stated, there are no "lies".
>
> The facts are that regardless of the physical server/storage device, there
> are different write strategies that one can choose to implement based on
> performance and data integrity requirements. This is an age-old design
> decision that goes back decades.
>

Since clearly neither you or Jan-Erik understand the issues being
discussed, here is some reading for you:

https://queue.acm.org/detail.cfm?id=2367378

There's no need to read the last bit about 4K sectors if you don't
want to as it's not applicable to this discussion.

In summary, yes, there has indeed been an historical issue with some
disks lying to the disk device driver about whether the data had made
it to permanent storage yet.

This has nothing to do with operating system level deferred write caching.
This is to do with some drives lying about the guarantee they are supposed
to give to the device driver controlling them.

What I don't know is if it's still a problem today.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.