External Harddrive vs. DVD Media
 

What are the pros and cons of backing up data on an external harddrive vs. putting them on DVD media?

What is more reliable?

Should I use flash memory sticks for backup?

If it's regularly updated data, I would use an external hard drive. If you're backing up for archiving purposes, use DVD. If a hard drive fails, you'll typically lose everything. DVDs can fail too, but the damage to data can be mitigated.

what's the size of data files you are looking to back up?

I would say anything less than 10 G goes to DVD/USB keys

40GB.

I could use DL DVD.

Depends on the type of backup and the retention time.

If it's just a regular backup, external hard drive or even USB flash drive would be just fine. Even if the device fails, you'd still have all the files on your computer and you can just get a new one to replace it.

The only danger is if both the hard drive in your computer and the external hard drive/USB flash drive die at the same time... but what are the chances of that?