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Status of the Channel Access Zippy Archiver (CZAR). B. Bevins , et. al. Outline. Status Performance Limitations Development Activities New Features Future Plans. Status. CZAR has been our production archiver for over a year. Common History API (HAPI) supplies data to:
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Status of the Channel Access Zippy Archiver (CZAR) B. Bevins, et. al.
Outline • Status • Performance • Limitations • Development Activities • New Features • Future Plans
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
Performance Data • 37,272 signals connected • Stores about 2 GB/day • About 810 GB of data available online dating back to June 2004 • 253.5 billion data points available online • Platform: • Redhat ES3, dual 3GHz P4, 16 GB memory, 1 TB RAID array
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
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!
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…
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
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
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
Status of the Channel Access Zippy Archiver (CZAR) B. Bevins, et. al.