Add find asset usage instructions

Author: grantfitzsimmons

sphinx/server_management/check_asset_usage.md

@@ -0,0 +1,18 @@
+# Check Asset Usage
+
+On the `assets1.specifycloud.org` instance, we host and manage most[^1] assets for hosted Specify Cloud users.
+
+To see the space used by all current asset directories, you can log into the VPS as `root` and run the following alias:
+
+```bash
+usage
+```
+
+This is defined in the `~/.bash_aliases` file, but it essentially runs this command:
+```bash
+du -sh * /home/specify/attachments
+```
+
+This can be adjusted and used elsewhere when needed. You can use `du -sh *` to effectively summarize the space used by a set of directories.
+
+[^1]: Some regions (including Swiss instances via Exoscale, KU collections on KUBI managed VMs) manage assets independently.