Encryption Bug or Feature?
Posted: Thu Jul 14, 2011 6:37 pm
I recently switched to encrypting data and thus had to do a complete file re-copy for the mirror directory I have at cloud storage. I expected this since the new files are indeed different than the old ones, particularly if compressed. That took about four days.
I then set up the scheduler to sync the directories and all seemed fine, incremental backups were fairly fast as they should be.
I then a few days later edited the task to exclude a particular directory that had large temporary-type files that were not worth keeping backed up. To my surprise, the entire task had to be re-started, copying all files once again (another four days).
I then did some testing with a small directory of 61 files, 500MB total. Here is what I found out:
1. If encryption is turned OFF, you can change a task and it will continue to do an incremental backup of only the changed/deleted files. If you stop the task in the middle, it will continue from where it left off. If you sync a task, then make a copy and paste the exact task, running the copy produces no files to sync, just as expected. Then, deleting the task copy and re-running the original produces no files to sync. All is good.
2. If encryption is turned ON, any change you make to a task will make that task re-sync as if there are no matching files on the ftp server, or if they are matching, they are considered changed and therefore have to be recopied. If you stop an encrypted task in the middle, it will have to start over from scratch. If you fully sync with encryption, then make a copy and paste the exact task, running the copy requires a full copy of the files up to the server. Deleting the task copy and re-running the original produces no files to sync.
It seems clear that when employing the encryption, any file comparison is not working as it assumes that all files on the ftp server are different and therefore a complete re-copy is required. It feels like the system is actually not doing a comparison but simply looking at a local database similarly to when you check the option to "only scan the source folder".
Bottom line, once you have a task that uses encryption, do not make any changes to that task or you will have to make a complete re-transfer on the next sync. It is as if it deletes the last sync database instead of modifying is for task changes or partial completions. Is this a feature or a bug?
Some clarity on how this all works would be greatly appreciated.
Thank you in advance.
Jeff
I then set up the scheduler to sync the directories and all seemed fine, incremental backups were fairly fast as they should be.
I then a few days later edited the task to exclude a particular directory that had large temporary-type files that were not worth keeping backed up. To my surprise, the entire task had to be re-started, copying all files once again (another four days).
I then did some testing with a small directory of 61 files, 500MB total. Here is what I found out:
1. If encryption is turned OFF, you can change a task and it will continue to do an incremental backup of only the changed/deleted files. If you stop the task in the middle, it will continue from where it left off. If you sync a task, then make a copy and paste the exact task, running the copy produces no files to sync, just as expected. Then, deleting the task copy and re-running the original produces no files to sync. All is good.
2. If encryption is turned ON, any change you make to a task will make that task re-sync as if there are no matching files on the ftp server, or if they are matching, they are considered changed and therefore have to be recopied. If you stop an encrypted task in the middle, it will have to start over from scratch. If you fully sync with encryption, then make a copy and paste the exact task, running the copy requires a full copy of the files up to the server. Deleting the task copy and re-running the original produces no files to sync.
It seems clear that when employing the encryption, any file comparison is not working as it assumes that all files on the ftp server are different and therefore a complete re-copy is required. It feels like the system is actually not doing a comparison but simply looking at a local database similarly to when you check the option to "only scan the source folder".
Bottom line, once you have a task that uses encryption, do not make any changes to that task or you will have to make a complete re-transfer on the next sync. It is as if it deletes the last sync database instead of modifying is for task changes or partial completions. Is this a feature or a bug?
Some clarity on how this all works would be greatly appreciated.
Thank you in advance.
Jeff