Docs / Yamcs Server Manual / Instance Services / Parameter Archive Service

Parameter Archive Service

The Parameter Archive stores time ordered parameter values. The parameter archive is column-oriented and is optimized for accessing a (relatively small) number of parameters over longer periods of time.

Class Name

org.yamcs.parameterarchive.ParameterArchive

Configuration

This service is defined in etc/yamcs.(instance).yaml. Example from a typical deployment:

yamcs.simulator.yaml 
services:
  - class: org.yamcs.parameterarchive.ParameterArchive
    args: 
      realtimeFiller:
        enabled: true
        flushInterval: 300 #seconds
      backFiller:
        #warmupTime: 60 seconds default warmupTime
        enabled: true
        schedule: [{startSegment: 10, numSegments: 3}]

This configuration enables the realtime filler flushing the data to the archive each 5 minutes, and in addition the backFiller fills the archive 10 segments (approx 700 minutes) in the past, 3 segments at a time.

yamcs.simulator.yaml 
services:
  - class: org.yamcs.parameterarchive.ParameterArchive
    args:
      realtimeFiller:
        enabled: false              
      backFiller:
        enabled: true
        warmupTime: 120 
        schedule:
          - {startSegment: 10, numSegments: 3}
          - {startSegment: 2, numSegments: 2, interval: 600}

This configuration does not use the realtime filler, but instead performs regular (each 600 seconds) back-fillings of the last two segments. It is the configuration used in the ISS ground segment where due to regular(each 20-30min) LOS (loss of signal), the archive is very fragmented and the only way to obtain continuous data is to perform replays.