Data gaps in shake data retrieved from fdsnws

Shakes R0353 and R7FA5 both have data gaps at the same time, twice today 08:51-08:56 and 14:28-14:35. After the gap, there is a frequency change in the data for about the same duration as the gap, almost like the missing data has been added to the following part of the trace. Investigating further for R7FA5, these gaps are present in data downloaded using obspy, but also on Swarm. The gaps have been occurring occasionally since the server came back online. I have asked the network manager at school to check for power outages, but there have been none. I can’t get to the Shake itself, due to being in lockdown.

Hi Mark, thanks for reporting. This is due to intermittent problems with our data server. I’ll spare you the details (which are way above my rudimentary knowledge of data servers anyway) and assure you that several people are doing their best to try and understand why this is happening and build a solution that will solve both this issue and the intermittent reliability problems that others have noticed.

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The same problems have re-occurred today (Saturday) on both of the shakes that I have checked, from 09:40 UTC today, but I guess you knew that already.

hi mark,

yes, we are currently experiencing intermittent issues with the server that we are aware of and working on. as we continue to identify the root cause of the problem it is possible there will be intermittent gaps in the data. rest assured we are doing our utmost to minimize these occurrences.

apologies for the inconvenience caused,

richard

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These issues highlight the need to take a copy of your daily files, otherwise you will lose data.
I do this for my 3 units using WinSCP to copy to DropBox on a schedule.
Here’s a typical script file that you can use:

open myshake:mypassword@127.0.0.1:33002
cd /opt/data/archive/2020/AM/RC144/SHZ.D
synchronize local
close
exit

In this case, my RShake is at a remote location and I’m using remote.it to open a peer-to-peer connection on Port 33002.


Your solution is far easier than the one I have just put in place using the technology that I am familiar with from 30 years ago. Here is a revised bash script for uploading today’s data file from my Shake to a NAS drive on a 15 minute basis using cron and, if it is between 01:00 and 01:59:59, it will transfer yesterday’s file as well, even on new year’s day. The script can take arguments of Today, Yesterday or All. It is not a better solution than yours, but it is a different one. It’s a long long time since I have written a shell script. I’m a bit uncomfortable with leaving my ftp username and password in a flat text file. My original version performed a binary transfer, but that corrupted the data file. An ASCII transfer works and I am able to read the data files from my NAS, which are more up to date and readily available than using fdsnws. I know I could collect fresh copies when I plot using ftp, but that seems unnecessary at the moment.

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