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DMT and NDS2

John ZweizigLIGO/Caltech

Ligo PAC, Caltech, Jan 12, 2009

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Overview

DMT and NDS2 are niche tools that provide data and some analysis S/W for:» Data quality monitoring» Detector characterization» Online analysis

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DMT Overview

Control room access to data, instrument status High bandwidth data distribution Minimal latency: data driven Provides

» Immediate status information to operators, Science Monitors, others» Data products

– Trend frames (statistics)

– Online calibrated h(t)

– Transient signal detections (for vetos)

– Data quality flag segments.

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DMT

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DMT Data Distribution

Data frames are broadcast to all DMT nodes» Currently broadcast over dedicated network by CDS frame broadcaster.» aLigo alternative: All DMT nodes could connect to CDS network.

Data push process on each node copies frames to shared memory.

Monitor processes register as consumers, read data directly from shared memory

Total latency <1s from end of data collection

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DMT Hardware

Server node» File server» DMT control services

– Alarm manager

– Trigger manager

– monitor name service

Communications node» Web server» Monitors/services needing external connectivity

Computation engines» SMP nodes located in MSR» Current work-horse: Sun X4600 (8-core 2.8GHz Opteron running Solaris)

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DMT Software

C++ class libraries from LIGO» I/O » Signal processing» Monitor base classes

Code imported from LAL (e.g. h(t) calibration function) Data monitors written by LSC collaborators (mostly

DetChar group) Packaged by DASWG for offline use

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Monitor Displays

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DMT Status

DMT has been running for ~10 years» Highly reliable, up-time > 99%» DMT displays used routinely by operators, SciMons, etc.

New online analysis support features tested in M9 (Dec 20-21, 2008)» h(t) generation» Multi-channel wavelet-based transient search (kleineWelle)

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NDS2

NDS2 provides NDS functionality to users outside of control room» Client/server model» User authentication» No direct connection to CDS (won't affect data flow)» Serve online, cached and archived data» Exchange of data between Ligo->Virgo for coherent analysis

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NDS2 Server Development

Prototype (β) NDS2 server software» Authentication by LIGO.ORG Kerberos» Memory buffering of recently used data.» I/O drivers implemented

– File systems

– GDS online shared memory partitions.

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NDS2 Clients

Existing client implementations» C library (nds1/nds2 client API)» C++ classes» NDS2Frame: write data as frames

Planned/In progress» Matlab client functions ()

– will allow use by existing matlab tools, e.g. ldv

» Port existing control room tools– dtt

– dv

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NDS2 Status

Test servers now running» S5 RDS data (from CIT archive)» A5 online data (from LHO CDS)» Test server installed at Syracuse

Use limited by scarcity of client software» No testing under heavy use» Usage patterns not determined» Expect I/O bandwidth (network and archive access) to be the only

performance bottleneck.