The Difference Between “Verify” and “Validate”
ChronoSync offers two methods to check that your data is accurate. This article will explain some of the differences between the two methods.
Verify
The first method can be employed while you run your Sync Task. The feature is ‘Verify Copied Data’. This is found on the ‘Options Panel’ of your Sync Task, in the ‘Special File/Folder Handling’ section.
When you enable this feature, each file that is copied while running the Sync Task is double-checked for accuracy. What happens is after a file is copied, it is read-back and compared to the original. Any discrepancy results in an error.
Only files copied get checked. Any items identified as already ‘in-sync’ are not checked by this setting.
This feature is great if you are targeting a frequently changing folder. This ensures your backed up files are accurate because if an incomplete or changing file gets copied, an error will get reported. If you also turn on ‘Auto-retry before handling errors’, located on the same panel in the ‘Reporting and Error Handling’ settings, and a file generates an error, the file is automatically retried.
Enabling this feature roughly doubles the amount of time it takes to run a Sync Task.
Validate
The second method you can employ is the ‘Validate’ feature. This is found in the Sync Task toolbar and under the ‘Actions->Synchronize->Validate’ menu item.
This feature in ChronoSync allows you to compare file data, resource forks, and metadata between your two targets without modifying either target. It will identify and report any discrepancies without any risk to your source or backup data. Remember, no data is changed on either Target. This is a detailed analysis to determine if each item matches exactly on both targets.
There are many data and metadata items you can configure ‘Validate’ to check. You can easily check for missing items by only enabling ‘Orphan files’. Or enable just ‘Data forks’ to check the contents of each file. If you decide to check Data forks, know that this is a very lengthy process, and every file in the Sync Tree is compared. Comparing some metadata or checking for orphans can be much faster.
The Validator pre-sets the Validate options based upon your current Sync Task settings, so if you have ‘Preserve Extended Attributes’ disabled, that item will not initially be marked for comparison. But you can customize the settings on the Validate Panel to meet your needs.
The Validator also allows you to automatically mark mismatched items for sync so they are updated the next time you run the Sync Task.
Be sure to enable ‘Post more detailed information to log’ when ‘Validating’ so that any issues are recorded in the Sync Task Log.
Conclusion
In either case, using Verify or Validate, the files are compared using a bit-for-bit compare on local and NAS targets. ChronoAgent targets are compared by generating a hash of the contents of the local and ChronoAgent file, and comparing the hash.
So ‘Verify Copied Data’ works to validate file data as it is copied. It does not compare files that are already ‘in-sync’.
And ‘Validate’ can be run as a separate process to compare file data on every item in the Sync Tree without modifying the contents of either target.
