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EarthScope / slarchive

a SeedLink client for archiving data streams
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slarchive restart creates overlaps #2

Open jschaeff opened 1 year ago

jschaeff commented 1 year ago

Hello,

I run slarchive processes with the -x option like this:

slarchive -l FO_00 -A /data/%Y/%H -x FO_00.state:600 bud-resif-a.u-ga.fr

Each time we stop/start the slarchive process, a 2h overlap appears in the data.

For instance, there was a restart at 2:14:13 UTC:

FO_ILLK_10_HNE    2023,124,20:00:00.960000 2023,125,02:14:13.035000  ==  200 4490416
FO_ILLK_10_HNE    2023,125,00:12:08.495000 2023,125,07:13:16.535001 -2.0h 200 5053609

The original data present on bud-resif-a.u-ga.fr does not have any overlap. I expected the state file option to avoid going too far in the past. Is this behaviour normal ? Can you help me understand what's happening ?

Cheers,

chad-earthscope commented 1 year ago

Hello @jschaeff ,

That is not expected behavior. The statefile should allow the connection and data flow to resume without any overlap or gap.

Two suggestions:

1) upgrade your ringserver to the latest version: https://github.com/iris-edu/ringserver/releases version v2020.075 contains a fix for resuming SeedLink connections. Although I would not have expected that issue to result in overlap, it may be related.

2) Provide the output when multiple -vvv flags are used with slarchive. There may be some clues during the negotiation phase.

jschaeff commented 1 year ago

We planned an upgrade of the ringserver in the coming weeks. I'll try to reproduce the problem. Meanwhile, I found out that the overlap corresponds roughly to the available data window published by the ringserver.

Cheers