I am not a member of the release team, and I am only speaking for myself.
The architecture requalification status for stretch  lists the
ppc64el porter situation as green, but there are three reasons why
the situation doesn't look that good to me.
First, official status of the porters:
- 1 DD
- 1 DM
- 2 no DD/DM
Is a DM enough, if the only DD gets killed by a car  the day after
the release of stretch?
Second, all 4 committed porters seem to be employees of IBM.
What happens if for whatever good or bad reason IBM decides in 2018
or 2019 to go away from ppc64el, and all 4 committed porters get fired?
The wording of the porter commitment is already limited to "I intend to",
and there is the single point of failure that one business decision
by IBM might reduce the number of porters immediately from 4 to 0.
Third, the skills of the committed porters for post-release work.
It is extremely valuable when people are doing manual and automated
testing and fix the usual porting issues prior to the release.
But the most important skills required post-release until end-2020 are
How many of the committed ppc64el porters are personally able to fix
difficult issues that require intimate knowledge of hardware, kernel
Lack of redundancy in these skills was the problem of the sparc port
in wheezy when the only skilled porter left.
The s390x port is yellow in the porters row due to having only two
Just looking at the numbers 4 sounds twice as good as 2, but for the
reasons explained above I think the ppc64el porter situation is actually
worse than on s390x, and should be marked as yellow or red.
 I do not wish bad to anyone, but from the Debian point of view
this is why reduncancy is required.
"Is there not promise of rain?" Ling Tan asked suddenly out
of the darkness. There had been need of rain for many days.
"Only a promise," Lao Er said.
Pearl S. Buck - Dragon Seed