How to make sure that my backup copy is intact and that it is not yet time to replace it?

Question

I have all my family pictures and videos in my hard disk. To safeguard them, my backup strategy is to make a copy on an external hard disk drive and keep it in a relative's house far away.

As soon as new pictures and videos arrive, I will bring it here and backup them up.

Also, once every month or so, I want to bring it here and make sure the backup copy is intact. If something is wrong, I will buy a new hard disk or take necessary steps to make sure a second copy is made quickly.

I need help with this second part. How can I make sure that nothing is wrong with the backup copy?

Some things that come to my mind are:

1. Somehow some files are missing.
2. All files are present, but they are corrupted somehow (players unable to read JPG, MOV etc..)
3. Hard disk sector level corruption.
4. Hard disk hardware failure.
5. ???

Except for the first thing, where I can simply find the no. of files and make sure the count matches, I don't know how to check for the other failure points.

How do I check all these? Is there anything else that I should check for whenever I bring it in?

It will be really great if one program or action can check for all these and report any problems with ANY of these so that I can go ahead with fixing them or making another good copy. How can make the whole process of verifying all these things streamlined?

P.S.
1. I do not use any backup software. I create my "copy" by just.. copying the files.
2. I am using Windows 7. So any tools you may suggest must work with it.

Answer 1

I would suggest you look into a software backup solution. Most of your concerns are covered by commercial backup solutions such as Ghost. You don't have to worry about certain missing files as most commercial solutions can make a single backup file for you (or split it into chunks). As long as all pieces of the backup are there and intact you should be able to restore from it.

Backup software offers a few more benefits for you:

• Compression and de-dupe features to save disk space
• Integrity checks on backup files to ensure there is no corruption in the backup
• Backup browsing utlities (ie. Ghost Explorer) so you can see whats in your backup and extract certain pictures when needed

among much more.

To check hard disk health, you could use a tool like HDTune. The free version has health status reporting/error checking if I remember correctly.

An alternate solution would be to store data in the cloud. You can get a lot of space fairly cheap these days, and as long as the photos don't come in by the thousands it shouldn't hurt your bandwidth limit. Initially, putting all old photos in the cloud may take some time, but adding bits and pieces later shouldn't take too long.

Answer 2

As pointed out by Olli, a backup software would make this easier.

You could also use a file checksumming utility to check the files, but that is rather time-consuming.

Finally, harddisks have built-in error detection and -correction mechanisms, so chances are good that any harddisk problem will manifest as a read error, not as silent corruption. So if you just read the whole disk (e.g. cating to /dev/null on Linux), most errors should show up.

Answer 3

At first, good investment might be adding second backup hard disk to the mix: one backup disk in your home, and another in remote location. And then every time you want to update your remote backup, you bring your disk from home to there and another disk back. That way there is always at least one disk in remote location. USB disks are pretty cheap, and then you can make backups as often as you want.

As of checking for backup integrity: that's pretty problematic, if you do not want to use any backup software, and if you can't start using one.

If you can buy second USB disk, I would recommend using Windows 7 built-in backup software. Windows automatically checks integrity of backups, so it saves one step for you. You can easily select what files you want to include in backup, so it doesn't have to be full backup of your computer.

Go to Control Panel -> Backup & Restore to configure backup software, or just to see what options you have.

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Backup integrity: one case is integrity of backup, and another is integrity of your originals. As of integrity of originals, you are almost out of luck with Windows; for example ZFS checks everything with cryptographic hashes against corruption, but there is no such solution for Windows, at least as far as I know. Keeping backups consistent is easy task with decent backup software, because data shouldn't change, so taking checksums is valid approach. If you take checksums for your working files (eg. those you have in your desktop), it's impossible to determine automatically which modifications are corruptions and which ones are genuine modifications.

Assuming you are using NTFS (default filesystem for Windows 7), it's journaled, so data shouldn't corrupt on filesystem errors (for example sudden power failure). This do not protect against underlying disk failures.

Answer 4

You can use RSYNC, a syncing tool for Linux (that also has some windows versions) to sync the two folders together. it takes a MD5 sum of each file, so it should report if there are errors during the sync process.

Or you can do a recursive MD5 Sums generation, but I'm not sure how to do that in Windows and compare them all.