Transcript CA Gateway Update Ralph Lange, BESSY Ken Evans Jr., APS Jeff Hill, LANL

CA Gateway Update
Ralph Lange, BESSY
Ken Evans Jr., APS
Jeff Hill, LANL
Berliner Elektronenspeicherringgesellschaft für Synchrotronstrahlung mbH (BESSY)
Overview
• As well CA server as CA client
• Usually runs on workstation with multiple
network interfaces
• Connects and separates networks in terms of
CA connections
• May use channel aliases (e.g. prefixes)
• Caches data
• Keeps connections alive
• Watchdog mode restarts on core dump
R.Lange, K.Evans, J.Hill: CA Gateway Update – EPICS Meeting Summer ’03 @ Diamond
CA Proxy Gateway
Allows CA between networks – configurable
through regular expression filters and CA access
security.
CA Clients
CA Gateway
CA Servers
R.Lange, K.Evans, J.Hill: CA Gateway Update – EPICS Meeting Summer ’03 @ Diamond
CA Proxy Gateway
Clients point to one proxy that distributes the
data with minimal impact on the private parts.
CA Clients
CA Gateway
CA Servers
R.Lange, K.Evans, J.Hill: CA Gateway Update – EPICS Meeting Summer ’03 @ Diamond
Caveats
• The Gateway always introduces a nonscalable bottleneck.
• A heavily loaded Gateway is a CPU and
memory consuming application that usually will
add overhead to the system.
• Bad configuration (too loose) may put more
load on the precious side instead of shielding
the IOCs.
R.Lange, K.Evans, J.Hill: CA Gateway Update – EPICS Meeting Summer ’03 @ Diamond
Recent Developments
 Gateway 2.0 (built against EPICS base 3.14.2)
is complete and working.
 More bugfixes in the Gateway, GDD, CAS /
CAC, important performance improvements.
 CAput logging feature (same as on IOC).
 Work on documentation (user manual) started.
BUT...
– Still some crashes (bad) and brain-dead hang
situations (much much worse).
Not yet officially released.
R.Lange, K.Evans, J.Hill: CA Gateway Update – EPICS Meeting Summer ’03 @ Diamond
Next Steps
Mid-July: Jeff and Ken will try to fix the hang
problems.
After that: Independent of their results a release
of the Gateway will be published.
 Either a beta release:
bad but still better than the old 3.13.2 based
Gateway.
 Or a stable 2.0:
quite good, but still bad, with lots of room for
improvements…
R.Lange, K.Evans, J.Hill: CA Gateway Update – EPICS Meeting Summer ’03 @ Diamond
Ideas
All the nice ideas for improvements:
• New hierarchical configuration file format to improve
performance (XML format?)
• New configurable watchdog (steal from Channel
Archiver)
• Better code documentation (using Doxygen?)
• CMLOG interface
• Provide some tabular usage and statistics info as web
page
• Use Data Access (new data object) instead of GDD
will be postponed until stable operation of the
Gateway is achieved.
R.Lange, K.Evans, J.Hill: CA Gateway Update – EPICS Meeting Summer ’03 @ Diamond