Fault-tolerance in EPICS

[Klemen Zagar <klemen.zagar@cosylab.com>]

Dear EPICS users,

Cosylab is working on a EU-funded project on "Dependable Distributed 
Systems" (DeDiSys -- http://www.dedisys.org). The goal of the project is to 
investigate and improve availability of distributed systems when faults are 
present (e.g., when the network is down or when nodes crash).

Since EPICS is an infrastructure for distributed systems, we are 
considering to apply the results of our research work to EPICS as well. In 
order to do that, we need input from those who use EPICS in production 
environments, such as yourselves.

We have prepared a general questionnaire that is expected to gauge 
requirements and expectations with regard to fault tolerant behavior. I 
kindly ask you too take a bit of your time and fill it in. It is 
conveniently available on the web:

  http://www.xlab.si/dedisys/start.php

(It takes about 20 to 30 minutes to make it through all the questions. If 
you wish to be kept informed of the project's progress, you might also wish 
to sign-in for the interest group.)

Since questionnaire is very generic, we would also welcome any additional 
input specific to EPICS, such as:

1. How frequent are failures at your facility?

2. How many of the failures are critical in a sense that operations of the 
entire facility are disturbed (e.g., a beam dump)?

3. How many failures could be attributed to EPICS or the control system 
itself (e.g., network congestions, defects in software, erratic behavior of 
controls hardware, ...)?

4. How many of these failures could EPICS help to avoid, and in what way 
(redundancy, replication of records, reliability APIs for developers, 
guidelines for development of reliable systems, ...)?

5. What is the typical down-time as a sequence of a failure?

6. Could EPICS be improved to help reduce this down-time? If so, how (e.g., 
allow reconfiguration without IOC restart, ...)?

In order to reduce traffic on the mailing list, please answer directly to 
myself, and I will summarize your contributions in a later posting.

Thank you for your cooperation,
  Klemen Zagar.

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 Klemen Zagar                                       Cosylab
                                     http://www.cosylab.com
 Email: klemen.zagar@cosylab.com           Teslova ulica 30
 Phone: +386 (41) 341-846                 SI-1000 Ljubljana
                                                   Slovenia
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