How to use extended system data for apps?

[chockalingam]

Hello Community,

I have 3 different applications running on CtrlX core X3 with external USB as extended system data memory.

1st Application - InfluxDB from CtrX store:  I have followed this guide https://developer.community.boschrexroth.com/t5/Store-and-How-to/IIoT-Use-ctrlX-CORE-as-a-monitoring...

It looks like, the setup is working fine and storing data. But yet to confirm, where the data is exactly stored - System data or sda1.

2nd Application - Container Engine App and one docker image(built and installed as snap). As far as I know and the knowledge gathered from forum, the docker prefers always the internal system data. So, the extended system data cannot be utilized really here. Please, correct me if I am wrong.

3rd Application - Custom snap with its files/folder mapped to appdata directory because I want to edit few configuration files during runtime. I guess, the appdata is part of internal system data only. Is there any possibility to keep or force this custom snap's files/folder to extended system memory and still make use of web UI based config file editing? 

Please, someone provide me general usecases where the extended system memory can be really employed and where not. 

Thanks & Regards

[MauroRiboniMX · Accepted solution]

Hello, 

Case 1: which is your influxDB configuration if you follow the guide you're set up to use the external. By the 2.2 version you would be oblied to use the external memory. You can both use the External memory as storage or as extension of the filesystem. 

Case 2: you are right.

Case 3: you can use the memory as External Memory in any app and just signed apps can use the extension of the internal memory for safety reasons. The UI actually is not showing them 🙂

Generally Extended data can be used by your apps if are signed or if you have root but you would not be in production mode. If you mount the memory as removable meda you can write inside as long as you have the "removable-media" plug in the app. 

Mauro