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DATE multi-stream recorder

A recorder that allows writing several output streams per GDC, primarily intended for CASTOR recording. It supports raw data and ROOT output formats, providing better use of CASTOR throughput and more efficient evacuation of the EB output buffer.

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DATE multi-stream recorder

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  1. DATE multi-stream recorder Irina Makhlyueva CERN PH-AID DATE v5 Training 14-15 March 2005

  2. Event Builder’s intrinsic recording capability is limited to a single stream, written either to a local disk, or to a FIFO (event descriptors) DATE multi-stream recorder (mStreamRecorder) permits to write several outputs stream per GDC. It is primarily intended for CASTOR recording mStreamRecorder: • runs on every GDC, reads events from the EB FIFO • started by the Run Control at “Start processes” phase • configured from $DATE_SITE_CONFIG/mStreamRecorder.config • writes log messages and statistics to infoLogger • supports two output stream formats: • raw data (see slides by Klaus), use RFIO for CASTOR recording • ROOT (this feature is still under development, to be released soon) • Better use of CASTOR throughput • More efficient evacuation of the EB output buffer DATE multi-stream recorder

  3. Event descriptors via SimpleFifo mStreamRecorder Events via EB Consumer API EB buffer stream (1) 1 Fatal condition signals (interrupts) stream (2) Event Builder 2 (optional) raw/ROOT transformation GDC disp ….. Dispatching algorithm stream (N) N File destination assigned to stream n n Config file ……….. 1 2 N Reporting to infoLogger/Stat Recorder shared memory (internal logging etc) GDC host GDC architecture with mStreamRecorer • the recorder consists of one disp and N × streamprocesses • all stream processes are completely independent on each other • disp reads the config file, configures and forks the streams • dispatching of events to streams, via FIFOs: • “round-robin” and “first-available” algorithms DATE multi-stream recorder

  4. How to run mStreamRecorder (1) • For CASTOR recording, install the latest production version of CASTOR client on all GDCs, the rpm can be downloaded from http://lxservb01.cern.ch/swrep/i386_redhat73/ • If needed, compile the mStreamRecorder components by running gmake in the$DATE_ROOT/mStreamRecorderdirectory • The executable files disp and streams are located in$DATE_ROOT/mStreamRecorder/Linux. Make sure that the owner (gid/uid) of these files has a write access to the CASTOR directories to be written to. • Important: set the suid and sgid permission bits for thesefiles: chmod ug+s disp stream This is needed because DATE processes are running under the dummy user “nobody”, having no appropriate write permissions • Prepare the configuration file (see next slides) and store it in $DATE_SITE_CONFIG/mStreamRecorder.config DATE multi-stream recorder

  5. How to run mStreamRecorder (2) • Add these lines to $DATE_SITE_CONFIG/SOR.commands script: if [ “${DATE_HOST_ROLE}“ = “gdc” ]; then ${DATE_ROOT}/mStreamRecorder/Linux/cleanup ${DATE_ROOT}/mStreamRecorder/Linux/disp fi This is needed, because the recorder is not yet fully integrated in the Run Control. • Enable online recording, by setting recordingDeviceparameter(s) to “:” in $DATE_SITE_CONFIG/ALLDETECTORS/RunParameters.rcParam or, via Run Control HI at the initialization stage, set Run Parameters → Define → GDC → Recording Device : DATE multi-stream recorder

  6. How to configure mStreamRecorder • Flexible, scalable configuration, currently defined via the ASCII file $DATE_SITE_CONFIG/mStreamRecorder.config • Almost no built-in default parameters: most of defaults must be explicitly defined • Free format (indentation, tabs, newlines and comments are for better readability only) • Up-to-date version of the reference guide: at www.cern.ch/Irina.M • The configuration file is a sequence of names and attributes: # a commentary line >COMMONattr1 attr2 … attr !! Common attributes >RECORDERS default_recattr1 attr2 … attr !! Default recorder attributes GDCname1 attr1 .. stream=str1name \ !! Special ttributes for … stream=… stream=… attr … !! …GDC gdcname1 GDCname2 … >OSTREAMS default_strattr1 attr2 … attr \ !! Default stream … attr … attr !! … attributes str1nameattr1 attr2 … attr !! Special attributes for stream str1name Attribute: name=value █ compulsory █ optional DATE multi-stream recorder

  7. Example 1 >COMMON method=2 Nstreams=3 loglevel=1 >RECORDERS default_recstream=default_str >OSTREAMS default_str sleep=1 fsize=1024 mxrecl=0 \ pool=alice_stage stager=stagealice \ path=/castor/cern.ch/alice/daq_dev/daq_recorder Examples (1) • The minimal configuration: all GDCs and all streams have the same attributes • Remarks: • All recorder parameters (here – only the stream name) are taken from default_rec (default recorder) definition • all stream parameters here are taken from the default_str definition • alice_stage and stagealice are standard ALICE pool and stager. Any other available stager/pool combination can be used instead • The number of streams per GDC is defined by Nstream=3 attribute in the >COMMON category, which has the highest precedence DATE multi-stream recorder

  8. # Example 2 >COMMON  method=1>RECORDERSdefault_rec    method=2 stream=default_strpcald04gdc Nstreams=4    \ !! the configuration for pcald04dgc     stream=default_str stream=public stream=test>OSTREAMSdefault_str   sleep=1 path=/local  mxrecl=0  \      pool=public  stager=stagepublic fsize=2047 !! fsize in Mbytespublic path=/castor/cern.ch/user/m/makhlyuitest=default_str path=/castor/cern.ch/user/m/makhlyui/test_dir Examples (2) • A more sophisticated configuration: individual GDC specs, a selection of different streams Example 2 • One GDC (pcald04gdc)takes its attributes fromdefinition. If this config file is used with multiple GDCs – the other ones will use the default_rec definition • If less that Nstreams are explicitly specified in the recorder, the appropriate number of default streams (default_str) is automatically added • method=1 (“round-robin”) will be used for all GDCs, because of the higher precedence of attributes in the >COMMON category • Streams public and test will take all their attributes, except path= , from default_str DATE multi-stream recorder

  9. Output file names pcald04gdc_run00000610_0_1.data file number (1,2…) GDC name run number stream number (0,1…) Status of mStreamRecorder • It is currently under test in DC6, with plain raw data streams and RFIO protocol for CASTOR • Still under development: • ROOT recording • Small changes in the configuration file parser (to accommodate ROOT and make a better use of defaults) • Configuration file checker • Integration in the DATE MySQL configuration DB • Full integration in the Run Control DATE multi-stream recorder

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