Keeping data safe - part four

As I said, the final part of this series would be about using services that let you forget about backup. That is, unless you are really devoted to avoid data loss. And we are, aren't we?

The cloud and it's services has made this much more available only over the last year or so. There's a host of online services:

• file storage (dropbox, Microsoft's onedrive (previously known as skydrive), google drive, jotta cloud, amazon, just from the top of my head)
• online office apps
• music and video streaming (spotify, wimp, youtube, hbo, netflix)
• todo-lists like Wunderlist
• online notebooks such as Evernote
• specialized storages like flickr let you store and share your images
• source code repositories
• e-mail - back in the day, it was downloaded to a file on your computer. today, it's a given that it's available online.
• and more

And with all of these services, backup is taken care of for you. In some cases, like a music streaming service, you don't have your music files backed up, but you have access to a whole library of music, that I pretty much can guarantee has a good backup strategy.

They also have apps for different systems, so you can get a hold of your stuff from work, from your cell phone, or from your linux laptop.

This means that you don't have to back up every single file on your existing drive. Instead, you can concentrate on the bits that aren't taken care of in the online services.

Imagine you're only using online services. Hard drive crashed? No problem. Just reinstall the operating system, and you're good to go. Seems too good to be true? Chrome OS already does this.

So what I'm suggesting is partly utilizing these services that already take care of the important part for you, so you can concentrate on actually generating more important personal memories (data). The different services offer different pricing models and features, so you need to consider them and make an educated choice for yourself.

Then know what's not included in the online storage, and assure that that part of your data is safely backed up as well.

Finally, I'd like to recommend taking a minute to value the different data. I mean, not every single file, but in groups: Family photos? Probably the one thing, next to work, that I'd really hate losing forever. Forever like in a house fire.

If an online service is terminated, there's a good chance your data won't be accessible. Likewise if your user is deleted for some reason, the terms of the service may state that they are required to keep your data only for a few hours...

Now the probability that your hard drive crashes simultanously to some critical error with your storage service, or very close to that, is of course very small. But it does exist. So if you really need to be sure, you should consider adding another backup to your system.

Keeping data safe - Part three

The previous part was about partitioning, and this part is about mirroring. As it turns out, not having to restore from a backup at all, is the most efficient way of avoiding data loss.

One way of ensuring your data is to mirror it continuously, usually by mirroring the whole disk. A drawback of data mirroring is cost - you need at least two disks, which means the price doubles. That is where partitioning steps up and says hey, you don't need to mirror everything - just put the important bits on the mirrored drive.  You usually don't have more than a 256 GB disk of personal data (I know many who have less  - a few have a lot more), which means you can have a small-ish set of drives for mirroring.

It actually makes sense not just because of the price tag, but because of the time it takes to rebuild the drive.

The benefit of this setup is quite easy to see, because recovering data from a hard drive failure can be very expensive, and always takes a certain amount of time. And even if you have a backup, you risk data loss because when did you perform a backup the last time? Even if it's a few hours ago, it doesn't help much if the work you did after, is gone.

How to set up mirroring

Strictly speaking, there are two ways of mirroring, one is by hardware, which you set up in your computer's BIOS, the other one is software based and can be done from the operating system.


In either case, you'll just see it as a regular hard drive on your system, but behind the scenes there are two drives, and every write action is performed on both disks. If one fails, the system automatically fails over to the working one. Hopefully you'll also get a message about the failure, but this depends on the software.

I'll just quickly go through the built-in feature in Windows 7. Go to Disk management (either click through Control Panel, Administrative tools, Computer Management , Storage and hit Disk Management - or just write disk management and click on "Create and format hard disk partitions" or from the run dialog, write diskmgmt.msc). Right click the disk you want to mirror, and select "Add mirror..."  This option is only available if a suitable disk exists. You can also remove mirrors the same way.

Windows 8 has a new feature called "Storage Spaces" that provides the option to mirror or distribute data over several disks. You'll find a nice review of this feature at howtogeek.com.

Things Takes Time

A word of caution here, (re)building an array of disks takes time. I have two 2 TB disks mirrored, and whenever I hit blue screen or reboot or system crash of any type (last time, way back in 2012) I couldn't really exhale until some 6 hours later... because meanwhile, the status of the array was "rebuilding". It basically means going through every bit on the one drive and replicating it on the other. And if the working drive fails during that time, you are in a hard place. (So if you're really really paranoid about losing anything, you might want to keep a spare drive handy, or even go for a heavier RAID setup, like RAID 5, which involves more hardware, but has a higher fault tolerance)



Windows does not do a good job in telling you if something's wrong with the mirror (it does hint something with a shout-out just after booting, but you have to sit there to notice it), so you need separate software. Or, you can go to Disk management, where you'll see the status of the array (I've highlighted the relevant bits). You see the two red disks, "disk 0" and "disk 2", they are both assigned to G: - if I go to Explorer, I'll just see one instance of G:.  You'll also see it reports a 50% overhead, which is correct. I have 2x 2TB = 4TB disk space, but only 2 TB is available. 50% is lost, because it's mirrored.

Next part will be about continuous backup, or using services that let's you forget about backup. Stay tuned.