Test of permanent per minute data storing on NANO SD and RPI
Posted: Sun Nov 15, 2020 2:08 pm
I my attempt to give the Meteohub user base a migration path to switch over to Meteobridge without loosing important features, I am experimenting with a Meteobridge add-on that allows to permamently store per minute data. Meteobridge versions NANO SD, PRO and RPI are capable to store hourly data persistently, but not per minute data. Currently per minute data is held in a RAM DB only and just for the last 72 hours. This allows for detailed daily charts and exports but not for long-term storage.
Reason behind this limitation was price of SLC flash storage (about $20 for a 2 GB microSD card) and higher flash wear because of more often writes. With the introduction of cheaper SLC microSD cards from Western Digital (former SanDisk) the price burden is no longer there. You can now buy 16 GB of SLC flash (SDSDQED-016G-XI) for about $30 at mouser (https://www.mouser.com/ProductDetail/Sa ... ecqg%3D%3D).
To reduce wear, the aggregation of data changes within an hour is still handled by the RAM DB only. This avoids to have min/max of hour/day/month/year/all data be recomputed and stored in flash every time a new data point comes in. However, per minute data is now also loggerd in the DB on flash storage to make it long-term available.
As you might assume this needs quite some changes, like
* major rework of data handling
* menu to edit per minute data on the web interface
* making data imports also on per minute base (when data granularity allows and the user is willing to tolerate the longer import times this takes)
Before going public, I would like to get feedback from beta testers. So if you are running a NANO SD or RPI and are interested to give it a try, please drop me a note.
"Storage" row adds an estimate how many days/years of additional data the SD card might be able to store. This is computed from the daily increase of the DB size compared to available storage. Therefore numbers will go crazy when you store large files on the SD card or import data. When Meteobridge is in standard operation for a day or two, you can expect realistic estimates.
Feature needs to be switched on here (please don't forget to press "Save and Apply".
Editing per minute data is working exactly as with hourly data before. Changes done on the per minute data are not propagated to hourly/daily/monthly/yearly data. If you want to achive this you also have to do changes on the "Edit Hour Data" tab.
Reason behind this limitation was price of SLC flash storage (about $20 for a 2 GB microSD card) and higher flash wear because of more often writes. With the introduction of cheaper SLC microSD cards from Western Digital (former SanDisk) the price burden is no longer there. You can now buy 16 GB of SLC flash (SDSDQED-016G-XI) for about $30 at mouser (https://www.mouser.com/ProductDetail/Sa ... ecqg%3D%3D).
To reduce wear, the aggregation of data changes within an hour is still handled by the RAM DB only. This avoids to have min/max of hour/day/month/year/all data be recomputed and stored in flash every time a new data point comes in. However, per minute data is now also loggerd in the DB on flash storage to make it long-term available.
As you might assume this needs quite some changes, like
* major rework of data handling
* menu to edit per minute data on the web interface
* making data imports also on per minute base (when data granularity allows and the user is willing to tolerate the longer import times this takes)
Before going public, I would like to get feedback from beta testers. So if you are running a NANO SD or RPI and are interested to give it a try, please drop me a note.
"Storage" row adds an estimate how many days/years of additional data the SD card might be able to store. This is computed from the daily increase of the DB size compared to available storage. Therefore numbers will go crazy when you store large files on the SD card or import data. When Meteobridge is in standard operation for a day or two, you can expect realistic estimates.
Feature needs to be switched on here (please don't forget to press "Save and Apply".
Editing per minute data is working exactly as with hourly data before. Changes done on the per minute data are not propagated to hourly/daily/monthly/yearly data. If you want to achive this you also have to do changes on the "Edit Hour Data" tab.