- CrashPlan for Home
This article is intended for CrashPlan for Home users. For Code42 CrashPlan and CrashPlan PRO documentation, read this page on our enterprise support site.
Adoption is the process of having one computer take over for another computer's identity, which helps you avoid repeating the potentially lengthy, initial backup of your data. The process also links the computer to your previously backed up files so they remain safely stored at the destination. This article is for users who are already familiar with adoption and want to take a deeper look at adopting identities and how it affects backup archives.
Adoption in depth
CrashPlan keeps a thorough and unique record of each computer's backup history, settings, and subscription information, which we call an identity. CrashPlan also assigns each device a globally unique identifier (GUID), which is used to associate the device with its identity and backup archive.
Adoption is the process of taking the identity and GUID from an old computer and transferring them to a new computer. This results in the new computer taking over the old computer’s history and backup archive.
The examples presented in this article assume that your backed up files have already been restored or otherwise moved to the new computer. When adopting a previous backup, all settings from the original computer are immediately applied to the current computer and the CrashPlan app will attempt to resume backup. If the previously backed up files are not restored to the computer before adopting, you may have an extended wait to restore your data while CrashPlan synchronizes your computer with the backup destination. Any files that cannot be found during synchronization will be flagged as "missing." To make the experience as fast as possible, the files should be placed in the same locations on the file system as they were on the old computer.
The first step in the adoption process is linking your new computer to the backup and settings on the computer you are replacing so that CrashPlan sees your new computer as a continuation of an existing backup.
CrashPlan is designed to start backing up right away. Every time you install the CrashPlan app on a computer, it assigns the computer a GUID, creates an identity, and prepares to start backing up that computer. This means that if you want this computer to take over an existing computer’s backup, you must instruct CrashPlan to replace the GUID and identity it just assigned to the new computer with the GUID and identity of your previous computer.
Adoption is the process you use to replace the GUID and identity on one computer with the GUID and identity of another computer from within the same user account. When you apply the GUID and identity from an old computer to a new computer, the old computer’s archive, licensing information, and previous settings are applied to the new computer. The identity and GUID that were created for the new computer before adoption are deactivated from the account and all data associated with that identity and GUID is deleted from CrashPlan's servers.
Your old computer, named "My Computer," has been fully backed up with CrashPlan and is being replaced by a newer computer called "My New Computer." When you install the CrashPlan app on "My New Computer," a new identity is generated for your account and both "My Computer" and "My New Computer" are active. When you adopt the identity of "My Computer," the identity of "My New Computer" is deactivated and removed from your account.
Behind The Scenes:
The following video by Customer Champion Xander B. shows what's happening behind the scenes.
Synchronizing with the destination
Once the identity file has been replaced, CrashPlan needs to gather information about your file selection, backup progress, and current status before it can resume backing up.
A synchronization process compares the cache indexes at the source computer with the backup destination. The CrashPlan app downloads information about your file selection, which contains all of the file path information for all of the files selected for backup. It's important to understand that these are the exact paths that were used on your old computer. If the file system on the new computer is different (e.g., different user name, different operating system), then CrashPlan won’t be able to find the new location of your files until you update your file selection to include the new file paths.
Additionally, your backup progress is downloaded from the backup destination and stored within the local cache. CrashPlan uses this information to resume backing up from where it previously left off.
On your old computer, named "My Computer," you had selected your user folder for backup (/users/MyName/), which was fully backed up. As long as all of the data from "My Computer" has been transferred or restored to "My New Computer" in the same location as the old computer (/users/MyName/), then the CrashPlan app will be able to resume backup from where it left off on the old computer without having to upload new data.
Verifying the file selection
When synchronization completes, a file verification scan begins and uses the cache files to detect any new, changed, or deleted files on the new computer.
This scan verifies that the data from the old computer is currently the same as what is stored on your new computer. If the files from the old computer are not found on the new computer, each file that is not found will be marked as "Missing." This file verification scan may look like your backup is starting over because the estimated time to complete doesn't account for the data that has already been backed up. CrashPlan is providing an estimate of time that assumes it has to perform a full backup. However, during the file verification scan, CrashPlan compares each block in your file selection to the blocks that have already been backed up in your archive. Once the blocks have been analyzed, CrashPlan only backs up the differences and the estimated time to complete will drop steadily.
CrashPlan scans the exact locations that were previously backed up on "My Computer" (/users/MyName/). If your username or the location of your files changed in any way, the file path may be different on "My New Computer" (/users/MyNewName/). If you changed operating systems, or if you didn't move or restore your data to the original location on the new computer, then CrashPlan marks files as "Missing" in your file selection. This is because CrashPlan no longer knows where the files are located so does not find them during the verification scan.
- If the file path information on the new computer is the same, CrashPlan scans the files on your computer to add any changed files (that you may have updated before adopting) or any new files (that you may have added before adopting) to the "to-do" list for backup.
- If the file path information on the new computer has changed, then CrashPlan will not be able to locate the files and the locations will be marked as "Missing." For CrashPlan to find and de-duplicate the files, you can either move the files to the original location, or update your file selection to include the new file locations.
The final step of the adoption process is resuming the normal backup operation and updating the archive at the backup destination.
The CrashPlan app uses the settings, cache, and "to-do" list that it has built to determine what needs to be backed up. That information is then compressed, encrypted, de-duplicated, and transferred to the destination to be stored in your archive. For more information, see How Backup Works.
The file verification scan detects that of your 200 GB backup, 2 GB of new files and changes have occurred since you switched to the new computer. The CrashPlan app then begins backing up only the 2 GB of new data and sending it to the backup destination without uploading your entire 200 GB of data again.