Access a System

Procedure

  1. Access Configuration Hub.
  2. In the Navigation section, select the system that you want to access.
    The System Properties section appears, displaying the following information.
    Table 1. Total Collectors and Utilization
    Field Description
    Total Collectors A chart that plots the total number of collectors in each state (for example, running, stopped).
    Write Cache Hit Ratio The hit ratio of the write cache in percentage of total writes. At the system level, this value is calculated as the average of the corresponding values of individual servers in the system.

    It is a measure of how efficiently the system is collecting data. Typically, this value should range from 95 to 99.99%. If the data is changing rapidly over a wide range, however, the hit percentage drops significantly because current values differ from recently cached values. More regular sampling may increase the hit percentage. Out-of-order data also reduces the hit ratio.
    Archive Compression The current effect of archive data compression. At the system level, this value is calculated as the average of the corresponding values of individual servers in the system.

    If the value is zero, it indicates that archive compression is either ineffective or turned off. To increase the effect of data compression, increase the value of archive compression deadbands on individual tags in the Tags section to activate compression.

    In calculating the effect of archive compression, Historian counts internal system tags as well as data source tags. Therefore, when working with a very small number of tags and with compression disabled on data source tags, this field may indicate a value other than zero. If you use a realistic number of tags, however, system tags will constitute a very small percentage of total tags and will therefore not cause a significant error in calculating the effect of archive compression on the total system.
    Write thread usage The percentage of the write threads currently in use by the system. At the system level, this value is calculated as the average of the corresponding values of individual servers in the system.
    Read thread usage The percentage of the read threads currently in use by the system. At the system level, this value is calculated as the average of the corresponding values of individual servers in the system.
    OUT OF ORDER WRITE RATE The number of out-of-order events per minute. At the system level, this value is calculated as the sum of the corresponding values of individual servers in the system.
    CONSUMPTION RATE The rate at which the archive disk space is consumed. At the system level, this value is calculated as the sum of the corresponding values of individual servers in the system.

    If the value is too high, you can reduce it by slowing the poll rate on selected tags or data points or by increasing the filtering on the data (widening the compression deadband to increase compression).
    FAILED WRITES RATE The number of samples that failed to be written per minute. At the system level, this value is calculated as the sum of the corresponding values of individual servers in the system.

    Since failed samples are a measure of system malfunctions or an indication of offline archive problems, this value should be zero. If you observe a non-zero value, investigate the cause of the problem and take corrective action.

    Historian also generates a message if a writing a sample fails. Note that the message only appears once per tag, for a succession of failed writes associated with that tag. For example, if the number displayed in this field is 20, but they all pertain to one Historian tag, you will only receive one message until that Historian tag is functional again.
    Table 2. Alarms and Events
    Field Description
    ALARM RATE The rate at which Historian is receiving alarms and events data. This data appears only if you archive the alarms and events data as well.
    Table 3. License
    Field Description
    HISTORIAN TAGS The number of tags authorized for this Historian installation by the software key and license.
    Note: If this field displays 100 tags and the number of licensed users is 1 client, you are probably running in demonstration mode and may have incorrectly installed your license key.
    USERS The number of users who have currently have currently logged in and accessed the system.
    DATA STORES The number of data stores in the system.
    Table 4. Graphs
    Name Description
    Read Sample Rate The trend of the average read sample rate across all the servers in the system per sample per minute. You can change the duration by selecting the drop-down list box in the upper-right corner of the graph.
    Receive Rate The trend of the recent rate at which the samples have been received per minute. You can change the duration by selecting the drop-down list box in the upper-right corner of the graph.


    The Servers subsection contains a list of distributed/mirror servers in the system, along with the status, the number of locations in each server, and a few other details.
    Tip: If you select the value in the LOCATIONS column, the number of locations, a list of distributed and mirror locations in the server appears. If you select a row, the same information appears in the Details section. You can add, remove, or freeze columns, in the table by selecting .
    The Locations subsection contains lists of distributed locations and mirror locations in the system. This subsection appears only for a horizontally scalable system. For each location, you can access the server machine name and the list of data stores. Similarly, for each mirror location, you can access the number of server machines and data stores in the group. In addition, the default location and data store in the system appear. You can change these default settings.
    Tip: If you select these numbers, a list of the server machines and data stores in the group appears, respectively. If you select a row, the same information appears in the Details section.