EPICS Controls Argonne National Laboratory

Experimental Physics and
Industrial Control System

1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <20182019  2020  2021  2022  2023  2024  Index 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <20182019  2020  2021  2022  2023  2024 
<== Date ==> <== Thread ==>

Subject: Re: Virtual circuit unresponsive on CA Gateway
From: Ralph Lange <[email protected]>
To: EPICS Tech Talk <[email protected]>
Date: Wed, 29 Aug 2018 09:12:08 +0200
Hi Sangwon,

As you say, possible limitations in network traffic processing might be something that affects Gateway operation on VMs. But I would expect this only to happen if a Gateway is very busy and/or forwards large amounts of data, e.g. images.

Channel Access' detection of unresponsive IOC connections is based on two mechanisms:
The beacons (by default 5065/UDP broadcasts) sent by the IOC (by default every 15 seconds) must reach the Gateway, which requires the caRepeater program to be running on the Gateway host before the Gateway starts.
If the Gateway does not receive a beacon within twice the configured beacon period, it uses the TCP connection to send a Channel Access alive message to the IOC. If the IOC does not return that alive message within 5 seconds, the Gateway declares the connection unresponsive.

Check if the IOC beacons are reaching the Gateway host. If that Gateway is not in the IOC's local network, the IOC needs to be configured to send beacons to the Gateway.
Also check if the VM's system clock is updating smoothly. I have seen VMs with jumping system clocks, which may affect the described detection mechanism.

Generally, I would suggest using a more recent version of base for the Gateway, e.g. 3.15.5. There is no problem running the Gateway on a different version than IOCs, and there are issues in Channel Access that have been fixed since 3.14.12.4 (December 2013). If you want a simple setup, create statically linked Gateway and caRepeater binaries. Those will not need an installation of EPICS Base to run.

Good luck!
~Ralph



On Wed, 29 Aug 2018 at 08:35, 윤상원 <[email protected]> wrote:

Hello Yong,

 

Thanks a lot for your reply with the information.

We are using the 3.14.12.4 for the CA gateways.

 

For the information, we were running virtualized CA gateways and yesterday we have built an additional CA gateway on another physical machine without virtualization for comparison of virtualized and physical CA gateways.

As the result, we observed that the message is often being occurred on a virtualized CA gateway but no such message on the physical machine based CA gateway.

In our case for the moment it seems the message is related with performance of system such as network traffic processing.

 

Thanks again.

 

Regards,

Sangwon

 

From: Hu, Yong <[email protected]>
Sent: Wednesday, August 29, 2018 12:29 AM
To:
윤상원 <[email protected]>; [email protected]
Subject: Re: Virtual circuit unresponsive on CA Gateway

 

Hi Sangwon,

 

Take a look at this: https://bugs.launchpad.net/epics-base/+bug/541238

At the end, Andrew said “Probably fixed in later versions of Base ….”, “R3.14.10 released”.

Which version of Base is your CA gateway built against?

 

Best,

Yong

 

From: <[email protected]> on behalf of 윤상원 <[email protected]>
Date: Tuesday, August 28, 2018 at 3:29 AM
To: "[email protected]" <[email protected]>
Subject: Virtual circuit unresponsive on CA Gateway

 

Hello,

 

We are running several CA gateways for providing access to PVs for clients including OPIs.

I observed the warning message Virtual circuit unresponsive on log files of the CA gateways.

For instance,

Aug 28 15:29:19 Warning: Virtual circuit unresponsive 172.17.101.21:5064

Aug 28 15:53:40 Warning: Virtual circuit unresponsive 172.17.101.80:5064

 

In addition, when the message is logged on a log file, connections to PVs of the IOC server related with the message (ex. 172.17.101.21) are disconnected.

At the time, connection to the same PVs which directly connects to the IOC server instead of CA gateway is still continued and client (camonitor) can receive changes from the IOC without disturbance.

 

For the information, we are running two versions of CA gateways, v2.0.4.0 and v2.1.0.

 

Could anyone please share any guidance or comments in the case?

Thanks in advance for your guidance or any comments.

 

Regards,

Sangwon


References:
Virtual circuit unresponsive on CA Gateway 윤상원
Re: Virtual circuit unresponsive on CA Gateway Hu, Yong
RE: Virtual circuit unresponsive on CA Gateway 윤상원

Navigate by Date:
Prev: RE: Virtual circuit unresponsive on CA Gateway 윤상원
Next: dbExpand.pl: cannot set PHAS to '' Benjamin Franksen
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <20182019  2020  2021  2022  2023  2024 
Navigate by Thread:
Prev: RE: Virtual circuit unresponsive on CA Gateway 윤상원
Next: Re: Virtual circuit unresponsive on CA Gateway 윤상원
Index: 1994  1995  1996  1997  1998  1999  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  <20182019  2020  2021  2022  2023  2024 
ANJ, 07 Sep 2018 Valid HTML 4.01! · Home · News · About · Base · Modules · Extensions · Distributions · Download ·
· Search · EPICS V4 · IRMIS · Talk · Bugs · Documents · Links · Licensing ·