April 28, 2005 EPICS Collaboration Controls Group Status of the Channel Access Zippy Archiver (CZAR) B. Bevins, et. al.

Controls Group April 28, 2005 EPICS Collaboration Outline  Status  Performance  Limitations  Development Activities  New Features  Future Plans

Controls Group April 28, 2005 EPICS Collaboration Status  CZAR has been our production archiver for over a year.  Common History API (HAPI) supplies data to:  XARR, StripTool, ArchiveViewer  hapiget (command line tool)  TCL programs using the Combat ORB A working prototype of a TCL archive viewer was written in an afternoon!  Specialized data collection such as event- triggered mode has reduced the need for other data collection tools.  Lead developer left for private industry

Controls Group April 28, 2005 EPICS Collaboration TCL Archive Viewer

Controls Group April 28, 2005 EPICS Collaboration Performance Data  37,272 signals connected  Stores about 2 GB/day  About 810 GB of data available online dating back to June 2004  billion data points available online  Platform:  Redhat ES3, dual 3GHz P4, 16 GB memory, 1 TB RAID array

Controls Group April 28, 2005 EPICS Collaboration Retrieval Performance

Controls Group April 28, 2005 EPICS Collaboration Limitations  Data acquisition engine has failed a few times  Scaling issues  Data retrieval server fails often, requiring constant monitoring  Possibly vulnerable to ill-behaved clients  Initial version is incompletely documented  Backup system only partially implemented and not automated

Controls Group April 28, 2005 EPICS Collaboration Limitations  Awkward management of data streams and groups  results in archiving unneeded streams  Scaling problem with original design  many data “chunks” contain only one point in time, resulting in very large database tables  causes slow data retrieval times  one system failure was a table index overflow!

Controls Group April 28, 2005 EPICS Collaboration Development Activities  Goal is to achieve a stable system requiring minimal monitoring  New version is test case project using more rigorous Software Engineering practices  Formal requirements, design review, development standards, code review, testing…

Controls Group April 28, 2005 EPICS Collaboration New Features  Automated backups to Computer Center tape silos (we’re a drop in the bucket to them)  Stream/group management policies and tools to assist in management  Data culling capabilities similar to Epics ADEL but will work on fields other than.VAL  Fixing and documenting the data retrieval access mechanism

Controls Group April 28, 2005 EPICS Collaboration Future Plans  Decommissioning system clogged with redundant and damaged data  Starting over with a clean database using data culling wherever appropriate  Managing stream requests so data is only archived for the period of user interest  High performance lossless data compression

Controls Group April 28, 2005 EPICS Collaboration Summary  Current czar archiver is meeting customer needs, but has problems  Development activities are underway to shore up holes in the current system  Planning to start with a fresh system that is more thoroughly engineered and tested up front

April 28, 2005 EPICS Collaboration Controls Group Status of the Channel Access Zippy Archiver (CZAR) B. Bevins, et. al.