No matter what type of hardware the host is using, no matter what kind of media they use for backing up your data and files, you, as a customer, should always have a backup of your entire website.
Your host may commited to keep 3 generations of backup of your site, daily, weekly and monthly, but they are many reasons that could fail the backup.
- e.g. The harddisk crashed.
- The server box failed completely.
- The server did not perform the backup completely.
- The server was hacked and all backup erased.
- the list goes on..
It doesn’t mean that your host is not good or not reliable, the fact is there are situation which is out of their control.
So, you should always keep backup of your website, at least once per week. Most control panel, like CPanel, has link on the control panel which allows user to download complete backup of the hosting account to your local harddisk.
Hope this help.