Re: SMR drive test 2; 128GB partition; no obvious corruption, much more sane behaviour, weird overprovisioning

[Marc Lehmann <schmorp@schmorp.de>]

On Thu, Sep 24, 2015 at 10:27:49AM -0700, Jaegeuk Kim <jaegeuk@kernel.org> wrote:
> > In the end, I might settle with -s64, and currently do tests with -s90.
> 
> Got it. But why -s90? :)

He :) It's a nothing-special number between 64 and 128, that's all.

> I just pushed the patches to master branch in f2fs-tools.git.
> Could you pull them and check them?

Got them, last patch was the "check sit types" change.

> I added one more patch to avoid harmless sit_type fixes previously you reported.
> 
> And, for the 8TB case, let me check again. It seems that we need to handle under
> 1% overprovision ratio. (e.g., 0.5%)

That might make me potentially very happy. But my main concern at the
moment is stability - even when you have a backup, restoring 8TB will take
days, and backups are never uptodate.

It would be nice to be able to control it more from the user side though.

For example, I have not yet reached 0.0% free with f2fs. That's fine, I don't
plan9 to, but I need to know at which percentage should I stop, which is
something I can only really find out with experiments.

And just filling these 8TB disks takes days, so the question is, can I
simulate near-full behaviour with smaller partitions.

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