The call logs on Android devices are stored in a database on the device, holding your records of incoming and outgoing calls. At this time, Android has no built-in mechanism that synchronizes this database with some online cloud service (compared, for instance, to the contacts data, that can be synchronized to your Google Contacts account).
If you consider your call logs something of any value, you will probably want to make sure this data is covered by some backup scheme – and this is what I am going to deal with in this post.
I use the Call Logs Backup & Restore app, which is free on Google Play store.
This post is written using v3.02 of the app.