hd firecuda

[Erich Dollansky]

Hi,

On Tue, 19 Dec 2017 14:46:06 +0000
RW via freebsd-questions <freebsd-questions at freebsd.org> wrote:

> On Tue, 19 Dec 2017 08:14:18 +0800
> Erich Dollansky wrote:
> 
> > The drives can now use a reserved space of the disk to store the
> > data. On long writes, this space will also be filled.     
> 
> It's unlikely that it would fall back to discarding useful cache in
> the SSD *after* filling the larger non-shingled area of the drive. If
> that bit of extra buffering made a useful difference they'd just
> increase the size of the non-shingled area.

how to increase the non-shingled area without shrinking the drive's
available size?
> 
> >  It could be also that
> > the disk fills first SSD and then the reserved space.    
> 
> If that happened I'd expect the speed to first drop to an intermediate
> speed of 50-100 MB/s, where the the non-shingled area is being written
> to, and then drop again when the non-shingled area fills. 
> 
> IMO what you are seeing is consistent with selective read caching plus
> write caching into the non-shingled area.  

How do you explain then the deep breath? What do I call a deep breath?
An access which takes more than a minute. It only happens when huge
amounts of data is written to the drive like updating sources and ports
tree and then starting to compile them.

I first thought that the first drive is faulty. But the second shows
the same behaviour.

Since these things are finished, the drive behaves basically like an
SSD.

Erich
> 
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