Access a System

Procedure

  1. Access Configuration Hub.
  2. In the NAVIGATION section, expand Systems, and then select the system that you want to access.
    The system appears in the main section.
  3. Expand the system in the main section.
    A list of servers in the system appears, displaying the following information.
    Field Description
    MACHINE NAME In a stand-alone Historian system, this column displays the host name of the Historian server. In a horizontally scalable Historian system, this column displays the host name of the primary server.
    STATUS The current status of the Historian system.
    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 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.
    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).
    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.
    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.
    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.
    MIN DISK SPACE LEFT The minimum free disk space in MB that must be available on the computer. If the minimum space required is not available when the collector starts, the collector will shut down.
    FAILED WRITE RATE (EVENTS/MIN) 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.
    MEMORY USAGE Indicates how much server memory is being consumed.
    READ QUEUE RATE (40 MSG/MIN) The number of read requests processed per minute, that came into the archiver from all clients.
    WRITE QUEUE RATE (MSG/MIN) The number of write requests processed per minute, that came into the archiver from all clients.
    MESSAGE QUEUE RATE (MSG/MIN) The number of messages processed per minute.
    READ QUEUE SIZE (EVENTS) The total number of messages present in the Read queue.
    WRITE QUEUE SIZE (EVENTS) The total number of messages present in the Write queue.
    MESSAGE QUEUE SIZE (MSG) The total number of messages present in the Message queue.
  4. To access the system performance, right-click the system (or select ), and then select View Server Performance.
    The <system name> - Performance section appears, displaying graphs for some of the metrics described in the previous table.