Jefferson Lab Report

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Jefferson Lab Report

• Karen S. White

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Status

• EPICS is performing well.
• We continue to occasionally have a problem when
  switching between CA Security configurations

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System Growth
1998 2003
IOCS 81 140
EPICS Records (K) 180 287
MEM IOC (Mb) 1504 2626
VME Crates 75 120
CAMAC Crates 105 105
Unix Workstations 30 50
X-terms 11 3
Segments 5 13
Unix Servers 6 20
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Managing a Large EPICS System

• Segmentation
• Growth
• Managing access and traffic
• Diagnostics
• Standardization
• Change Management

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Segmentation

• System divided into 13 independent segments to
  facilitate
• Availability
• Resource Management
• Maintenance
• Each segment has its own server, network, IOCs,
  etc
• Except a single Oracle database server is
  shared between all segments

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Growth

• Upgrades to accommodate growth
• Faster IOCs
• More IOCs
• More Memory on IOCs
• More Unix Consoles
• More Memory on Unix Consoles
• More Network Bandwidth

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Nameserver

• Nameserver
• Reduces IOC load and network traffic due to
  broadcast for name resolution
• Provides PV location info to tools that do not
  need to connect
• Improves client connection time (2x)
• Used by all operations client for 1.5 years
  very reliable no failures
• Handles over 6 million requests per day

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Gateway

• From APS/BESSY
• Used to group multiple requests for the same
  signal
• Concentrates communication from many clients to a
  single client
• Reduces IOC load and network traffic due to
  broadcasts for name resolution
• Reduces the number of connections to IOCs
• Facilitates easy management of access from
  different CS segments

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Standardization

• Standardization of common elements can improve
  developer productivity and software
  maintainability. Examples
• PIOC
• General purpose tool built on PCAS
• Developer does not need to know details
• Ensures consistent usage
• Standardized Serial, GPIB PLC drivers

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Diagnostics

• Alarms warns of oncoming IOC problems (be
  careful what you put on IOCs)
• Monitoring of Unix and network resources
• Diagnostic program to check for hardware
  communication errors
• Status pages with IOC information
• Control System startup and checkout procedures

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Controlled Change

• With a large number of developers and
  applications, changes must be well planned and
  documented
• Versioning
• Roll back procedures
• Testplans with auto e-logs

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General Comments

• Keeping a large EPICS system up and running
  requires careful planning, diagnostics,
  monitoring
• The development and maintenance processes are
  made more efficient by using standards,
  versioning and release control

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