See page 252 of this book about taking the store down for maintenance.
You have the ability to close your shop and put up a "Down For Maintenance" page at your discretion. When your shop is down for maintenance, all shop functionality will be disabled. This might be necessary if development work is being done on your site or if you are going on vacation and do not want people to be able to order items as you will not be able to ship them.
To disable your ZenCart shop do the following...
1. Log on the administrative control panel.
2. Go to "Configuration -> Website Maintenance"
3. Click the first item that says "Down for Maintenance: ON/OFF".
4. Select radio button "True" and click "update" button.
5. To bring back up your shop back online, do the same but select False in the radio button.
