How to show maintenance mode page in magento (website under construction) when your website is under maintenance?
If you want your Magento website to show in maintenance mode, you will have to do two things.
1. Create a file name maintenance.flag in your magento root directory. Contents under this file doesn’t matter, you can keep it empty.
2. Change the maintenance file (located in magento root -> errors -> default directory) to show proper message when user visits your website.