Document existing storable objects and their status regarding Hashed storage

doc/administration/repository_storage_types.md

@@ -27,6 +27,9 @@ of load in big installations, and can be even worst if they are using any type o
 Last, for GitLab Geo, this storage type means we have to synchronize the disk state, replicate renames in the correct
 order or we may end-up with wrong repository or missing data temporarily.
 
+This pattern also exists in other objects stored in GitLab, like issue Attachments, GitLab Pages artifacts, 
+Docker Containers for the integrated Registry, etc.
+
 ## Hashed Storage
 
 Hashed Storage is the new storage behavior we are rolling out with 10.0. It's not enabled by default yet, but we
@@ -67,3 +70,23 @@ To migrate your existing projects to the new storage type, check the specific [r
 [ce-28283]: https://gitlab.com/gitlab-org/gitlab-ce/issues/28283
 [rake tasks]: raketasks/storage.md#migrate-existing-projects-to-hashed-storage
 [storage-paths]: repository_storage_types.md
+
+### Hashed Storage coverage
+
+We are incrementally moving every storable object in GitLab to the Hashed Storage pattern. You can check the current
+coverage status below.
+
+Not that things stored in S3 compatible endpoint, will not have the downsides mentioned earlier, if they are not
+prefixed with `#{namespace}/#{project_name}`, which is true for CI Cache and LFS Objects.
+
+| Storable Object | Legacy Storage | Hashed Storage | S3 Compatible | GitLab Version | 
+| ----------------| -------------- | -------------- | ------------- | -------------- |
+| Repository      | Yes            | Yes            | -             | 10.0           |
+| Attachments     | Yes            | Yes            | -             | 10.2           |
+| Avatars         | Yes            | No             | -             | -              | 
+| Pages           | Yes            | No             | -             | -              |
+| Docker Registry | Yes            | No             | -             | -              |
+| CI Build Logs   | No             | No             | -             | -              | 
+| CI Artifacts    | No             | No             | -             | -              | 
+| CI Cache        | No             | No             | Yes           | -              |
+| LFS Objects     | Yes            | No             | Yes (EEP)     | -              |