DDS slow-down on large scale system.

TSTN-023

When deploying the Telescope and Site systems for the main telescope at NCSA we started to experience severe startup slow downs. These occurrences affected components both using SalObj and SAL (e.g. CCCamera) and manifested mainly by timeout's in getting historical data followed by the communication being seriously unstable.

With the deployment of a new cycle (with xml 6.1) we decided to take a more close look at the problem. This tech-note describes the findings, proposed solutions and points of concern for the future deployment.

Links:

• Publication URL: https://tstn-023.lsst.io
• Alternative editions: https://tstn-023.lsst.io/v
• GitHub repository: https://github.com/lsst-tstn/tstn-023
• Build system: https://github.com/lsst-tstn/tstn-023/actions/

Build this technical note

You can clone this repository and build the technote locally with Sphinx:

git clone https://github.com/lsst-tstn/tstn-023
cd tstn-023
pip install -r requirements.txt
make html

Note

In a Conda environment, pip install -r requirements.txt doesn't work as expected. Instead, pip install the packages listed in requirements.txt individually.

The built technote is located at _build/html/index.html.

Editing this technical note

You can edit the index.rst file, which is a reStructuredText document. The DM reStructuredText Style Guide is a good resource for how we write reStructuredText.

Remember that images and other types of assets should be stored in the _static/ directory of this repository. See _static/README.rst for more information.

The published technote at https://tstn-023.lsst.io will be automatically rebuilt whenever you push your changes to the master branch on GitHub.

Updating metadata

This technote's metadata is maintained in metadata.yaml. In this metadata you can edit the technote's title, authors, publication date, etc.. metadata.yaml is self-documenting with inline comments.

Using the bibliographies

The bibliography files in lsstbib/ are copies from lsst-texmf. You can update them to the current lsst-texmf versions with:

make refresh-bib

Add new bibliography items to the local.bib file in the root directory (and later add them to lsst-texmf).