ShadowProtect and Free Space On a Hard Drive

ShadowProtect and Free Space On a Hard Drive

July 19

Space: the final frontier. These are the voyages of StorageCraft Technology…

There’s a lot we can talk about when it comes to space. This article is designed to help you understand how much free space you need for various StorageCraft ShadowProtect and StorageCraft ImageManager processes, and to offer some best practices when it comes to monitoring free space on various volumes.

The term “free space” sounds metaphysical, but don’t worry. We’re not trying to have a philosophical discussion about what space really is and I’m not concerned about whether or not anything is actually free. When we talk about free space, we’re specifically referring to how much free space is on a hard drive. It’s a very simple concept: free space is the part of the hard drive that’s writeable, but that doesn’t always technically mean it’s empty.

Removing Files From Free Space

The fascinating thing about free space is that it’s not always, well, free. If you were to create enough files to fill your hard drive and then “delete” half of its contents, nothing would actually be deleted. All you’ve done is erase the files from an index, and the space on your hard drive where you deleted the files or folders is marked as writeable again. For all intents and purposes, this writeable space effectively becomes free space once more, although whatever existed on the drive in that part of the sector is still there until something writes over it.

Digging through this supposedly free space to recover “deleted” files is how forensic recovery software works. The fact that there’s data that hasn’t been overwritten is why it’s important to destroy a hard drive or use data shredder software when you’re done with them (assuming you want to get rid of the data). You never know what sort of personal info might be hiding on your hard drive, and there are those that will steal identities by recovering “deleted” personal information for illegal use.

But there’s more to say about free space, especially with regard to ShadowProtect products.

Having Enough Free Space

The ShadowProtect program only takes 50MB of space on your hard drive, but making sure you’ve cleaned things up before taking your first backups can help reduce overall space taken up by backups. Doing a simple disk cleanup can actually help free up some space before you resort to deleting files buts you may want to do both.

Free Space Notifications

Knowing when free space is running low is critical to making sure you keep taking backups. That’s why it’s important to monitor your free space. Not only do you need space on the hard drive you’re backing up, you also need space wherever you decide to store the backups. If the destination folder for your backups fills up, you’ll no longer be able to take backups.

Luckily, there’s an easy solution: StorageCraft ImageManager.

ImageManager and ShadowProtect both have notification capabilities, but ImageManager can email you whenever free space in a specific folder starts to run low. Simply open ImageManager, highlight the desired managed folder, click notification settings and check the “low free space” radio button. You can tell ImageManager to email you when the volume fills up to a certain point. It’s up to you to choose how full it should be before you’re notified. Click the email setup tab and type in your server and email info, click ok, and you’re set.

ImageManager consolidation and retention policies will also affect how quickly your free space is filled, so be sure to adjust these so that your destination volume doesn’t fill up too quickly.

Backing up Free Space for Forensic File Recovery

But wait, there’s (even) more. While using the ShadowProtect backup job wizard, you’ll find an option that allows you to backup the free space on your drive. Why would you want free space in your backup? Well, remember the forensic recovery software we talked about? As mentioned, free space isn’t always free, it’s just writeable disk space. If you’ve put information on a disk and deleted it, the information is still there until you write over it. That means that if you backup the free space on a volume in addition to used space, you’ll retain the ability to forensically recover things that were deleted from within the backup. The disadvantage is that including free space will actually take up more space on the drive housing the backup. I bet you never thought emptiness could take up space, did you?

Not Enough Free Space to Recover? Shrink the Volume

We’re not done yet, there’s another cool free space feature. Suppose you’ve got 100 GB of space but the volume you backed up is 101 GB. You’re out of luck right? You’ll have to buy a larger drive and recover to that, right? Wrong. If you need to restore a volume to a drive that doesn’t have enough free space, you can shrink the volume you’re restoring. In many cases you can shrink it enough to fit on the volume you’re restoring to. Here’s how:

(Note: There are a handful limitations to the following process, please refer to our knowledge base article before you attempt to shrink your volume so that you don’t run into any problems, there are also some great screen shots.)

In ShadowProtect, click “explore backups” on the left-hand side. Browse to the image you’d like to shrink, move through the wizard to the “explore options” section. Uncheck the “mount backup as read-only” button and then finish the wizard.

Now, in ShadowProtect, select “dismount backup image” and another wizard will open. Find and select the mounted image and click next. On the “backup image dismount options” screen, check the “save changes to incremental file” box and be sure to put a check in the “shrink volume” box. Finish the wizard.

Following this process, you’ll likely be able restore the shrunken volume to the drive you’ve got available*. Once the shrinking completes, attempt the restore again. Assuming the volume you’re restoring has shrunken to fit, you’re restore will go off without a hitch.

*While trying to restore a volume larger than you have room for can cause trouble, restoring a volume smaller than the space you have won’t. Once a restore takes place, the restored image will reclaim any extra free space on the drive as writeable free space.

The End of Free Space

It sounds simple and maybe obvious, but it’s essential to keep track of your space. A corollary to Parkinson’s law states that data expands to fill storage space that’s available, and in general, it’s true. We almost always need more space so it’s important to think about when you’ll need how much more space to accommodate ever-expanding data.  Don’t wait until you’re totally out of space to get more. As always, be sure to accommodate for future growth when it comes to backup and disaster recovery. Data storage is vital to successful backup and disaster recovery plans, so be sure there’s no end to your free space.

Photo Credit: Mr. Physics via Compfight cc