MQTT and SD Card

[Chema]

Hi

I have a question related to MQTT and how it works. I am a newbie with MQTT and its functions so I must apologize if this question is very basic. Anyway here I go: I know that WeeWX writes every 5 minutes in the SD Card (as usual unless user changes this setup) and MQTT sends to the website every 2.5 seconds the generated information. Does it mean that every 2.5 seconds writes in the SD Card and in the WeeWX data base? I am concerned about too much writes could damage the SD Card. 

best regards. 

[vince]

On Wednesday, July 17, 2019 at 11:19:12 AM UTC-7, Chema S. wrote:

I have a question related to MQTT and how it works. I am a newbie with MQTT and its functions so I must apologize if this question is very basic. Anyway here I go: I know that WeeWX writes every 5 minutes in the SD Card (as usual unless user changes this setup) and MQTT sends to the website every 2.5 seconds the generated information. Does it mean that every 2.5 seconds writes in the SD Card and in the WeeWX data base? I am concerned about too much writes could damage the SD Card. 

MQTT sends a 'network' message to the MQTT broker you have specified.  So it's talking to a process on the other end.  It's not writing to disk locally.

[Pat]

In addition to this, weewx may not always send to MQTT every 2.5 seconds. This MQTT publish interval is based on your weather station hardware and how often weewx gets data from it. This is called the LOOP. 

Some LOOPS are every 20 seconds. As a result weewx's MQTT message will be every 20 seconds. 

Some LOOPs can be 60 seconds, so MQTT will only get a message every 60 seconds.

And so on, dependent on the LOOP interval. 

With that said, Tom has weewx running on a Raspberry Pi and it has pretty good uptime. 4 years 7 months and counting. 

[Chema S.]

Thank you for your replies. In my case the loop is every 2.5 seconds and I thought that every loop was written in the card. I am working with a Raspberry Pi as you can imagine. Now I have clear that it is not like that. Maybe I'll give MQTT an opportunity and learn something else :-)

Best regards

(Sorry for my English)