[arm-allstar] AllStar reliability -- was: dtmf macros for repeater control
Fred Moore
fred at fmeco.com
Mon Dec 28 09:26:56 EST 2015
Thought I would add to the Linux reliability with this story.
I was asked to link an access control system between Orlando and Chicago
for one of my customers. Deploying the two Linux machines took longer
than getting this done. The design was simple as the access system
could be expanded via serial ports, it was as simple as creating an SSH
tunnel between the systems, and routing the serial data over link. Each
server was sitting in a company data center, we are talking about 24/7
conditioned power and proper cooling.
The design, was simple, on each side
(Orlando)
Access Control 485 network --- RS-485 box (serial) -- Linux PC
-- INTERNET --
(Chicago)
Linux PC (serial) RS-485 box -- Access Control 485 network
This was before small hardware boxes were created to do exactly this..
Fast forward 3.5 years later, I get a phone call from my contact in
Orlando, with a question, where did we put that link server at, Under
the desk where the access control PC sits, says I, we moved that years
ago, but I can't find the link PC, we know its still running as the
Chicago and Orlando are still talking.
I went over and we found the missing server, After following the network
cable under the floor we found the server, behind a wall that had been
built when they decreased the size of the data center. Apparently the
data center guys moved the PC running the access control system, didn't
see the small headless PC sitting under the desk, the movers came in on
a Friday night moved the desk, found the server, didn't call anyone, and
the construction crew that weekend just built the wall about 5 feet in
front of it. The wall was constricted to decrease the size of the data
center in order to decrease the AC load. So here it was 3.5 years later
still running untouched behind a wall without air conditioning for at
least 2 of the 3.5 years, happily maintaining a ssh link.
BTW this system was running Debian. The other thing I need to tell you
is this occurred around 9 years ago. So at the time the system was
deployed around 11.5 years ago. Since then the OS is far better than
it was back then. I am primarily a BSD guy as I grew up on mainframes
and Unix, the only reason I chose Linux for this job was because a
couple of the IT guys wanted to see Linux actually do something as they
had never played with it, since I already was a BSD guy it was still
simple to do.
The lessons here are simple don't run any software you don't need, an
just let it run, do it's job and don't play with it after its working.
Fred
On 12/27/15 8:10 PM, David McGough wrote:
> Hi Willem,
>
> I thought I'd comment about my experiences with AllStar reliability. My
> experience has been that there are two parts to reliability:
>
> First, there is the day-to-day "situation normal" scenario. If a SCOM or
> Link-Comm gets 5 nines of up-time, I'd give AllStar a solid 4 nines. This
> difference is largely due to my mucking around with configs at 2AM, etc.
>
> As a real-life example, I just got the stats off a custom mini-ITX PC
> based AllStar setup that I built: Linux uptime: 72 days. AllStar uptime:
> 71+ days. TX time: 271+ hours. TX time today: 3+ hours. What makes this
> interesting is that this PC is located at 1700 feet HAAT, in a cabinet on
> a TV tower--a REALLY hard to reach place! And, the PC uptime reflects the
> last time I was doing maintenance in person, at that cabinet!
>
> Second, there is the infrequent "oh $@&#" scenario--something like a
> direct lightning strike. Here is where is find AllStar GREATLY superior.
> For perhaps $200, I can have a complete, spare AllStar system sitting on
> the shelf, ready to go (and, I do--several, in fact). I never had spare
> Link-Comm's sitting around, due to cost; so, minimally, we were down for
> days (or weeks) waiting on parts or repairs. Once a replacement
> controller was obtained, all the levels had to be manually reset and it
> had to be reprogrammed, manually, via DTMF (yuck!). This is all moderately
> tedious, frequently requiring the repeater to be sitting on the test
> bench, with an experienced technician performing the setup.
>
> Comparatively. with AllStar, I can deploy a spare system in minutes. No
> audio level woes (since these are set digitally), etc. Just drop the
> backup config files in place, plug in URI hardware and go. It is literally
> that simple!
>
> The biggest argument I hear from people is: oh, that's PC based!!!
> Everybody knows that PC's lock up all the time!! Well, maybe PC's running
> some unmentioned very popular commercial OS--but, not Linux! If you've got
> stable hardware, Linux just sits there and runs. And, runs. And, runs.
>
> So, obviously, I'm sold on the AllStar solution--hence why I'm investing
> so much time helping to improve and promote it.
>
>
> 73, David KB4FXC
>
>
> On Sun, 27 Dec 2015, Willem Schreuder wrote:
>
>> On Sun, 27 Dec 2015, Doug Crompton wrote:
>>
>>> I might add though that Allsar makes an excellent repeater controller
>>> and migrating to using it rather than the expensive dedicated
>>> controllers might be something to look at.
>> That is what we are working towards, but I also hate to throw away
>> perfectly good controllers. They have proved to be really reliable so we
>> still need to convince the public service folks that we can reproduce that
>> reliability. I would argue that the flexibilty of Allstar far outweighs
>> potential reliability, but you probably have heard all the counter
>> arguments.
>>
>> So this may be a temporary use case, but it would still be something
>> useful to be able to do.
>>
>> -73 Willem AC0KQ
>>
>> ================================================================
>> Dr. Willem A. Schreuder, President, Principia Mathematica
>> Address: 445 Union Blvd, Suite 230, Lakewood, CO 80228, USA
>> Tel: (303) 716-3573 Fax: (303) 716-3575
>> WWW: www.prinmath.com Email: Willem.Schreuder at prinmath.com
>> _______________________________________________
>>
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--
Fred Moore
email: fred at fmeco.com
fred at safes.com
phone: 321-217-8699
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