Re: Ultra5 successful install - PGX64 issues

[Frank Scheiner <frank.scheiner@web.de>]

On 04/22/2018 09:17 PM, Frank Scheiner wrote:
>> Some switches support a half-duplex back pressure form of flow control.
> 
> I'll try that now. According to the documentation my switch can create 
> back-pressure as form of flow control.

Yesterday after I activated flow control on the switch, the 712/80 got 
back after a while and finished the `apt list --upgradable` command with 
output - in between the journald of systemd crashed and restarted. 
Reissuing the same `apt [...]` command worked without problems. On the 
switch's port summary I could now also recognize that the host that acts 
as NFS server now got pause frames submitted by the switch - so the flow 
control is working.

I then tried to install `joe` and when `update-alternatives` started it 
again lost the connection to the NFS server. :-( It didn't recover from 
that - at least not during the time I waited for it - so I powered the 
712/80 down.

I thought maybe switching back to System V init might ease the load a 
little bit for the 712/80, so I upgraded the file system with a c8000 
(incl. newer patch level for the kernel) and removed systemd afterwards 
(also from initramfs).

I then ran some benchmarks without any issues in between.

Today I still have the problems described in [1] when doing `apt install 
[...]` or `apt remove [...]` but now the 712/80 recovered each time so 
far after a while, so it looks like an improvement to me. Look at the 
timings for `apt remove [...]`:

```
root@hp-712:~# time apt remove -y joe
[ 8794.150750] nfs: server 172.16.0.2 not responding, still trying
[...]
[ 8794.962227] nfs: server 172.16.0.2 not responding, still trying
[ 8795.074226] nfs: server 172.16.0.2 OK
[...]
[ 8797.271834] nfs: server 172.16.0.2 OK
[ 8802.242312] nfs: server 172.16.0.2 not responding, still trying
[...]
[ 9235.937478] nfs: server 172.16.0.2 OK
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages will be REMOVED:
   joe
0 upgraded, 0 newly installed, 1 to remove and 0 not upgraded.
After this operation, 2,086 kB disk space will be freed.
(Reading database ... 41128 files and directories currently installed.)
Removing joe (4.6-1) ...
update-alternatives: using /usr/bin/jmacs to provide /usr/bin/editor 
(editor) in auto mode
update-alternatives: using /usr/bin/jpico to provide /usr/bin/editor 
(editor) in auto mode
update-alternatives: using /bin/nano to provide /usr/bin/editor (editor) 
in auto mode
Processing triggers for mime-support (3.60) ...
[ 9357.992385] nfs: server 172.16.0.2 not responding, still trying
[...]
[10055.370493] nfs: server 172.16.0.2 not responding, still trying
[10055.709731] nfs: server 172.16.0.2 OK
[...]
[10057.212469] nfs: server 172.16.0.2 OK

real    22m0.853s
user    1m3.264s
sys     0m43.875s
```

...the `apt install -y joe` done beforehand took about 41 minutes. So 
the 712/80 can recover from the described problems, but package 
management should really be done from a more powerful machine, at least 
when running diskless.

[1]: https://lists.debian.org/debian-hppa/2018/04/msg00007.html

Cheers,
Frank