Difference between Scaleup and Scale out in Azure
Scaling out: adding more instance, more computer
Scalling up: adding more resourece like as more memory more processor power.
Scaling out is adding more equivalently functional components in parallel to spread
out a load. This would be going from two load-balanced web server instances to
three instances. Scaling up, in contrast, is making a component larger or faster to
handle a greater load
Scale out the web app manually
Scale out the web app and verify the performance improvement
In the Azure portal, in the pane for your web app, under Settings, select Scale
out (App Service Plan).
On the Configure page, set the Instance count to more (e.g. 5), and then select Save.
Switch to the Cloud Shell that’s running the client app. You should see fewer
requests failing with errors, though you’ll still see some that time out.
Scale up a web app manually
Scale up the web app and monitor the results
1- In the Azure portal, return to the page for the App Service plan.
2. Under Settings, select Scale up (App Service plan).
3. Select higher pricing tier (e.g. the P2V2 pricing tier) and then select Apply. This pricing tier gives you
420 ACU (more than four times the power of the S1 pricing tier), and 7 GB of
memory, running on a Dv2-Series VM. But this VM costs four times the cost of
running the S1 pricing tier.