Scoring a million pixels

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Profile David Anderson
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Message 1833609 - Posted: 2 Dec 2016, 8:05:07 UTC
Last modified: 2 Dec 2016, 8:06:02 UTC

Yesterday I tried scoring 1M pixels (previously I'd been scoring 100K or so at a time).

The scoring itself was successful. However, the result was a directory containing 3M files. A script then moves these files into a 1-level hierarchy of 4096 directories. This script ran very slowly, like 1 file every 2-3 seconds. Apparently the filesystem on the Atlas machine does not implement directories in an efficient (constant-time) way. Surprising.

Anyway, I changed things so that the Condor jobs that score pixels put the output files directly into the hierarchy, so we no longer have super-big directories. Hopefully this will fix things.
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Profile Raistmer
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Message 1839128 - Posted: 31 Dec 2016, 14:53:00 UTC - in response to Message 1833609.  

Hello David

Any news how Nebula development going?
Did you able to score whole dataset already? If not what is current highest value of pixels processed at one pass?
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Message boards : Nebula : Scoring a million pixels

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