Changelog and Documentation for storage migration of project attachments

changelogs/unreleased/hashed-storage-attachments-migration-path.yml

+---
+title: Hashed Storage migration script now supports migrating project attachments
+merge_request: 15352
+author:
+type: added

doc/administration/raketasks/storage.md

 # Repository Storage Rake Tasks
 
 This is a collection of rake tasks you can use to help you list and migrate 
-existing projects from Legacy storage to the new Hashed storage type.
+existing projects and attachments associated with it from Legacy storage to 
+the new Hashed storage type.
 
 You can read more about the storage types [here][storage-types].
 
+## Migrate existing projects to Hashed storage
+
+Before migrating your existing projects, you should 
+[enable hashed storage][storage-migration] for the new projects as well.
+
+This task will schedule all your existing projects and attachments associated with it to be migrated to the 
+**Hashed** storage type:
+
+**Omnibus Installation**
+
+```bash
+gitlab-rake gitlab:storage:migrate_to_hashed
+```
+
+**Source Installation**
+
+```bash
+rake gitlab:storage:migrate_to_hashed
+
+```
+
+You can monitor the progress in the _Admin > Monitoring > Background jobs_ screen.
+There is a specific Queue you can watch to see how long it will take to finish: **project_migrate_hashed_storage**
+
+After it reaches zero, you can confirm every project has been migrated by running the commands bellow. 
+If you find it necessary, you can run this migration script again to schedule missing projects.
+
+Any error or warning will be logged in the sidekiq's log file.
+
+You only need the `gitlab:storage:migrate_to_hashed` rake task to migrate your repositories, but we have additional
+commands below that helps you inspect projects and attachments in both legacy and hashed storage.
+
 ## List projects on Legacy storage
 
 To have a simple summary of projects using **Legacy** storage:
@@ -73,35 +106,73 @@ rake gitlab:storage:list_hashed_projects
 
 ```
 
-## Migrate existing projects to Hashed storage
+## List attachments on Legacy storage
 
-Before migrating your existing projects, you should 
-[enable hashed storage][storage-migration] for the new projects as well.
+To have a simple summary of project attachments using **Legacy** storage:
 
-This task will schedule all your existing projects to be migrated to the 
-**Hashed** storage type:
+**Omnibus Installation**
+
+```bash
+gitlab-rake gitlab:storage:legacy_attachments
+```
+
+**Source Installation**
+
+```bash
+rake gitlab:storage:legacy_attachments
+
+```
+
+------
+
+To list project attachments using **Legacy** storage:
 
 **Omnibus Installation**
 
 ```bash
-gitlab-rake gitlab:storage:migrate_to_hashed
+gitlab-rake gitlab:storage:list_legacy_attachments
 ```
 
 **Source Installation**
 
 ```bash
-rake gitlab:storage:migrate_to_hashed
+rake gitlab:storage:list_legacy_attachments
 
 ```
 
-You can monitor the progress in the _Admin > Monitoring > Background jobs_ screen.
-There is a specific Queue you can watch to see how long it will take to finish: **project_migrate_hashed_storage**
+## List attachments on Hashed storage
 
-After it reaches zero, you can confirm every project has been migrated by running the commands above.
-If you find it necessary, you can run this migration script again to schedule missing projects.
+To have a simple summary of project attachments using **Hashed** storage:
+
+**Omnibus Installation**
+
+```bash
+gitlab-rake gitlab:storage:hashed_attachments
+```
 
-Any error or warning will be logged in the sidekiq log file.
+**Source Installation**
+
+```bash
+rake gitlab:storage:hashed_attachments
+
+```
+
+------
+
+To list project attachments using **Hashed** storage:
+
+**Omnibus Installation**
 
+```bash
+gitlab-rake gitlab:storage:list_hashed_attachments
+```
+
+**Source Installation**
+
+```bash
+rake gitlab:storage:list_hashed_attachments
+
+```
 
 [storage-types]: ../repository_storage_types.md
 [storage-migration]: ../repository_storage_types.md#how-to-migrate-to-hashed-storage