Improve Badger docs (#824)

Signed-off-by: Yuri Shkuro <[email protected]>

content/docs/next-release-v2/apis.md

@@ -171,5 +171,4 @@ grpc_cli ls localhost:16685
 [sampling.proto]: https://github.com/jaegertracing/jaeger-idl/blob/main/proto/api_v2/sampling.proto
 [grpc-reflection]: https://github.com/grpc/grpc-go/blob/master/Documentation/server-reflection-tutorial.md#enable-server-reflection
 [gogo-reflection]: https://jbrandhorst.com/post/gogoproto/#reflection
-[storage.proto]: https://github.com/jaegertracing/jaeger/blob/main/plugin/storage/grpc/proto/
-storage.proto
+[storage.proto]: https://github.com/jaegertracing/jaeger/blob/main/plugin/storage/grpc/proto/storage.proto

content/docs/next-release-v2/badger.md

@@ -3,7 +3,18 @@ title: Badger
 hasparent: true
 ---
 
-[Badger](https://github.com/dgraph-io/badger) is a local file storage embedded within Jaeger.
+[Badger](https://github.com/dgraph-io/badger) is an embeddable persistent key-value database, similar to RocksBD. The Jaeger binary embeds Badger and can use it as a storage backend without external dependencies.
+
+**Pros**:
+  * Badger stores data in the local file system and therefore can survive process restarts.
+  * A single node can sustain high throughput.
+
+**Cons**:
+  * It is only suitable for a _single-node deployment_, so it cannot scale horizontally for higher data volumes.
+  * It is not possible to share a single Badger instance between multiple Jaeger processes, such as **jaeger-collector** and **jaeger-query**, therefore it is usually only used in the **all-in-one** configuration.
+    * NB: it is possible to share a single Badger instance between multiple processes if you use Badger with the [remote storage](../tools/#remote-storage-component) component.
+
+## Configuration
 
 See [sample configuration](https://github.com/jaegertracing/jaeger/blob/main/cmd/jaeger/config-badger.yaml).
 

content/docs/next-release-v2/tools.md

@@ -30,11 +30,11 @@ docker run \
 
 ## Remote Storage (component)
 
-**jaeger-remote-storage** implements the [Remote Storage gRPC API][storage.proto] and proxies it into one of the regular Jaeger backends. It can be useful in the situation when we want to run a full deployment of Jaeger components, e.g., separate collector and query services, but use a single-node storage backend like the memory store or Badger. Without the remote storage, the single-node backends can only be used with all-in-one since they cannot be shared between multiple processes.
+**jaeger-remote-storage** implements the [Remote Storage gRPC API](../apis/#remote-storage-api) and proxies it into one of the regular Jaeger backends. It can be useful in the situation when we want to run a full deployment of Jaeger components, e.g., separate collector and query services, but use a single-node storage backend like the memory store or Badger. Without the remote storage, the single-node backends can only be used with all-in-one since they cannot be shared between multiple processes.
 
 At default settings the service listens on the following port(s):
 
 Port  | Protocol | Function
 ----- | -------  | ---
 17271 | gRPC     | [Remote Storage API](../apis/#remote-storage-api)
-17270 | HTTP     | admin port: health check at `/` and metrics at `/metrics`
+17270 | HTTP     | admin port: health check at `/` and metrics at `/metrics`