When you back up with CrashPlan for Small Business, your data is not uploaded in its original state. Before uploading your files, CrashPlan splits each file into blocks of data which are then compressed and deduplicated.
Compression: The Code42 app utilizes an advanced, lossless compression algorithm to minimize the data footprint in our cloud. Files are uncompressed when you restore them. This compression can be very efficient depending on the size and type of file. For example, if you are backing up a 10 GB documents folder, CrashPlan could potentially compress it to 3 or 4 GB before uploading.
Deduplication: CrashPlan deduplicates data at the block level, so it is very efficient at what it needs to back up and store in the cloud. For example, if you had 2 files that were 1GB each and identical, CrashPlan would only need to back up 1GB of data. Even if there were small changes to the files, CrashPlan would only need to back up those changes specifically, not the whole file. It can do this because the file is split up into blocks. Only the new blocks would be uploaded for that file.
Comparing Archive Size and File Selection
You can check the compressed size of your archive as well as how it compares to the the amount of original data you have selected for backup in the CrashPlan for Small Business Administration Console:
- Sign in to the Code42 console.
- On the left sidebar, click Devices and then click Active.
- On the list of devices, click the name of the Device you're interested in to open device details.
In the device details page, the number labeled Used Storage is your compressed archive size. This is the total amount of data you've uploaded from that device for all time, after compression and upload to the cloud. The number labeled Selected is the original size of the files selected for backup in the Code42 app. The size of the file selection in the console reflects the amount of data CrashPlan found in its last scan.
Because everyone's data is different, the discrepancy between the archive size and file selection will be different between devices. If you are worried that there might be data missing from your backup, the best way to determine if a file has been backed up is not to look at the archive size, but to try to Restore files. Any file that is available to restore in the Code42 app is a file that was successfully backed up before.