I managed to sum metrics with meta service but I still want the stacked curves.

Hello, 

I would say you can define manually the curve from the dedicated menu: 

Not sure how it will fit in your specific use case. 

Best

My concerns are rather related to how unite performances from different hosts than to stack them

Then you should take a look at 

@sims24 this pack seems to be perfect to my use case.

I tried to load it through Plugin Pack Manager but it is not visible.

I tried to install it manually and I got this output:

>root@op-centreon-web centreon-engine]# yum install centreon-pack-applications-monitoring-centreon-sql-metrics
Loaded plugins: fastestmirror
Loading mirror speeds from cached hostfile
 * base: mirror.ufscar.br
 * centos-sclo-rh: mirror.ufscar.br
 * centos-sclo-sclo: mirror.ufscar.br
 * epel: d2lzkl7pfhq30w.cloudfront.net
 * extras: mirror.ufscar.br
 * remi-php80: mirror.pit.teraswitch.com
 * remi-safe: mirror.pit.teraswitch.com
 * updates: mirror.ufscar.br
No package centreon-pack-applications-monitoring-centreon-sql-metrics available.
Error: Nothing to do

edit: nevermind, it was a license issue

@sims24 really great plugin pack

I managed to perform these traffics into this graph inverting traffic IN curves from OUT

My issue is when I stack traffic out curves, they transverse to negative axis like this:

Shouldn't traffic out remain stacked at positive axis? Is this a case for bug report?