Where to Store a Backup?

When considering where to store your backup, some important things to consider are how much will you backup, how often, and the costs involved.

It is a good idea to keep at least one backup onsite, for fast restoration in the case of accidental deletion, and at least one backup off-site for safety in case there is a serious disaster such as fire, theft, flood, etc. An offsite backup may involve placing a DVD or external hard drive at a different location. But the easiest and best option for offsite backup is to subscribe to an online backup service.
 

Storage Type	Storage Capacity	Cost of Device	Ongoing Costs	Speed	Pros	Cons
External Hard Drive	High	Low per gigabyte	None	Fast	Easy to backup, easy to automate.	Liable to same damage as master drive if directly connected, and at the same location. Since a virus or lightning strike can corrupt both at the same time.
CD/DVD	Low-Medium	Low	Moderate	Slow	Portable	Burning CD's and DVD's is time consuming.
Solid State Storage, such as memory stick.	Low 1GB-2GB	High per gigabyte	None	Medium	Portable, good for storing small files, such as documents.	Low capacity, easily lost or stolen.
Online Backup	Medium-High	Free to Setup	Set monthly fee, Or even free for up to 2GB.	Medium	Easily accessible, Can be fully automated, Off-site, no devices required.	Large transfers may take a long time.
Other computer connected through network	Medium-High	Medium	None	Fast	Fast. Software, and technical skill required.	If the computer storing the backup is onsite, it is at risk of same dangers as the computer being backed up.
Magnetic Tape	High	Relatively high	Relatively low	Medium	For large data storage, it's slightly cheaper than storage on a hard disk.	Magnetic tapes are more vulnerable to errors. Short storage life.