You need to keep backup copies of your CMS database. No matter which CMS you choose to use, a huge part of your web site, including all the content, is probably stored in a database, rather than text files and images.
(Actually, a few CMSs do avoid databases altogether, and store all the content in text files. But these "flat-file" systems are used extremely rarely.)
A database can't be copied as easily as ordinary files. Usually, you want to export the database to a file. Then you backup that file.
Depending on your setup, you may already have a good tool for backing
up the database. For instance, if you
use Aegir to manage a Drupal multisite, you
Backup. That task backs up not only the database, but
also the site files.
However, the time sometimes comes when you just need a quick backup of
the database. If you don't have some other quick way to do this, just
ssh in and run this command:
mysqldump -u username -p yourpassword databasename > Filename.sql
If this command seems cryptic to you,
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