Incremental Backup is missing files when backing up
Has anyone else encountered this? I'm using Acronis Home 2010.
When making an incremental backup, it doesn't seem to be adding files to the backup that have changed -- only adding ones that are new. I recently restored a backup from May 31, 2011 and found that many of my files (bookmarks, log files) were from 2010 (from a date of my last FULL backup), even though they had been updated continuously. Many other things were properly updated though. There are no errors in the logs for the backups.
Am I misunderstanding the point of an incremental backup? Is what I want simply a differential backup -- I simply want to add all updated/changed files to the backup archive and have it delete the old ones -- in essence to mirror of my current drive.
Thanks in advance!
Thanks for responding! Yes, I am referring to backing up files as an image with Acronis True Image Home.
Interesting, let me see if I understand this. I'll use an example --
Let's say I do a full-backup today. 10 gigs of files.
Then next week I do an incremental backup -- what that is going to do is update files ALREADY in the backup archive, if those files have been modified/changed on my hard drive. In other words, it's not going to add files into the backup archive that are new/modified on the hard-drive, unless they were already in the backup archive previously when I did my full-backup.
Is that the correct understanding?
So if I just want to have a backup, that takes a snapshot of all of the current files on my hard drive every-week in it's own self-contained archive -- what I really want (if I am planning to use only ATI) is just to do a full-backup every time, correct?
This is the description from the help file:
There is one section that requires some clarification see the end of this post.
==============================
Full, incremental and differential backups
Acronis True Image Home 2011 offers you three backup methods:
1) Full: contains all of the data at the moment of the backup creation. It forms a base for further incremental or differential backups. It can also be used as a standalone backup.
2) Incremental: Only those files will be included which have been changed since the LAST backup.
3) Differential: Only those files will be included which have been changed since the last FULL backup.
We suggest you to choose one of the following three approaches of using the backup methods:
"Full" - A standalone full backup might be an optimal solution if you often roll back the system to its initial state or if you do not like to manage multiple files.
"Incremental" - These are most useful when you need frequent backups and the ability to roll back to a specific point in time. Having created a full backup once, if you then create an incremental backup each day of a month, you will get the same result as if you created full backups every day. Incremental images are considerably smaller than full or differential images.
Such a backup scenario may consist of a weekly full system backup with intermediate, daily backups that cover data that was changed since the LAST backup.
This scenario, while requiring less storage space and time for the daily backups, will require more work on your part to provide recovery after a system crash. In the event of a Thursday crash, you would have to recover the last FULL backup followed by the Monday, Tuesday and Wednesday incremental backups.
"Differential" – is an intermediate between the first two approaches. It is also good when the conditions are intermediate. Each differential backup includes all the files changed since the last full backup. It takes less time and space than "Full", but more than "Incremental". The good thing is that recovering is simpler than for (2) - you'll have to recover the last full backup and the last differential backup.
Examples and recommendations
To choose a desired backup method, you need to configure a custom backup scheme. For more information see Custom scheme.
You can choose any approach for each of your backup projects according to their size and frequency of file modifications. For example if almost all the included files appear changed before an incremental backup starts, the incremental backup will be almost of the same size as a full backup would be. If so, let it be "Full" to simplify the recovery.
A "differential" backup scenario uses the same weekly full system backup with the backup of files that have changed since the last full backup on a daily basis.
While this scheme takes up progressively more storage space as each new day of the week passes, a recovery would only involve two backups - the last FULL backup followed by the previous day's differential backup. Many users prefer this method as it simplifies recovery and most backups are done overnight.
In these examples, the only differences in the two backup scenarios are:
Incremental backups require less storage space while differential backups require more.
Incremental backups require all of the backups used for that week in order to do a complete recovery, while the differential backup only requires a maximum of two backups at any given time.
An incremental or differential backup created after a disk is defragmented might be considerably larger than usual. This is because the defragmentation program changes file locations on the disk and the backups reflect these changes. Therefore, it is recommended that you re-create a full backup after disk defragmentation.
If you lose an incremental backup version or it becomes corrupted, all later incremental backup versions will be unusable.
Deleting backups and backup versions
You may want to delete backups and backup versions you no longer need. Acronis True Image Home 2011 stores information on the backups in a metadata information database.
Therefore, deleting unneeded backup files by using Windows Explorer will not delete information about these backups from the database, and Acronis True Image Home 2011 will consider that they still exist.
This will result in errors when the program tries to perform operations on the backups that no longer exist. So you must only remove obsolete backups and backup versions by using the tools provided by Acronis True Image Home 2011.
To delete an entire backup:
On the main screen, find the corresponding backup box, click Operations, and then click Delete backup.
When you delete an entire backup, all its versions will be deleted as well.
To delete a specific backup version:
On the main screen, find the corresponding backup box, click Explore and recover or Explore all versions.
In Backup explorer, right-click the version you want to delete, and then click Delete version.
When you delete a backup version, please remember that this version may have dependent versions. In this case the dependent versions will be deleted as well, because data recovery from such versions becomes impossible.
If you delete a full backup version - the program will also delete all subsequent incremental and differential versions till the next full version.
If you delete an incremental backup version or a differential backup version - the program will also delete all subsequent incremental versions till the next full or differential version.
==============================
This paragraph (see below) suggests it is up to the user to recover each incremental. It is my understanding that ATIH will recover the full backup and all the incrementals required up to the users chosen incremental - the point in time they want to go back to. I appreciate that all the intervening incrementals must be readable.
So Sunday has a full backup and we do incrementals for Monday thru Saturday and I want to restore the system back to Thursday I select the Thursday incremental and ATIH will recover automatically with no user intervention, the full backup from Sunday and then the incrementals for Monday thru Thursday and all files that were changed added, deleted etc. will be exact as of the time of the Thursday incremental.
"This scenario, while requiring less storage space and time for the daily backups, will require more work on your part to provide recovery after a system crash. In the event of a Thursday crash, you would have to recover the last FULL backup followed by the Monday, Tuesday and Wednesday incremental backups."
The wording of the paragraph above suggests it is down to the user - that is the point that needs rewording if my understanding is correct.
Thanks for responding! Yes, I am referring to backing up files as an image with Acronis True Image Home.
Interesting, let me see if I understand this. I'll use an example --
Let's say I do a full-backup today. 10 gigs of files.
Then next week I do an incremental backup -- what that is going to do is update files ALREADY in the backup archive, if those files have been modified/changed on my hard drive. In other words, it's not going to add files into the backup archive that are new/modified on the hard-drive, unless they were already in the backup archive previously when I did my full-backup.
Is that the correct understanding?
So if I just want to have a backup, that takes a snapshot of all of the current files on my hard drive every-week in it's own self-contained archive -- what I really want (if I am planning to use only ATI) is just to do a full-backup every time, correct?
No, if a file is created after the full was made it will also be included in the incremental.
A backup is an image of the disk all changes to the disk will be backed up as Seekforever says.
Try it...
take a full backup
create a new file
take an incremental backup
delete the file
and then use the recovery option to recover the files you just deleted.
Then hopefully you should have some confidence in what is happening.
If you do a full backup to day. 10 GB of files.
Then only file A is changed. When you run the next backup as an incremental or differential, ATI will create a second TIB with that file inside.
Then only file B is changed. When you run the next incremental, only file B is included. When you run the next differential, file A and file B are included. Now you have 3 TIB files. The full, and 2 partials (incrementals or differentials).
Then you delete file A and you change file C only. When you run the next incremental backup, file C is included. If it is a differential, file B and file C are included. Now you have 4 TIB files.
At this point, here is the content of your backup for an incremental backup
- TIB 1: full
- TIB 2: file A
- TIB 3: file B
- TIB 4: file C
For a differential:
- TIB 1: full
- TIB 2: file A
- TIB 3: file A, file B
- TIB 4: file B, file C
What Pat L says is correct but you can recover an image or any individual file(s) by browsing any backup file, full, incremental or differential. As you switch dates on the selection screen you can see the files for a given location changing (assuming they have changed). ATIH aggregates all the backups in the set to show you all the files that can be recovered and allows you to select the date.
So if in the example above file A was changed to have different content on each day then you can recover the content for the day of your choice or recover all the days to different locations to see what did change in the file.
I hope that helps.
Interesting! Well it seems there must be a problem with the way I'm doing the incremental backup, because there are no excluded folders/files, but even the most recent archive files do not contain the appropriate up-to-date versions of files on my hard drive.
Edit: I think I see my problem... At one point I deleted some older incremental backups, thinking I did not need them, but as I recall, I used Windows Explorer. Perhaps that's where the issues were introduced.
Dave,
Do not delete any backup file created by ATI with Windows Explorer. In fact, because of bugs, do not delete any backup file create by ATI with ATI itself :-)
Your backup chain is now compromised. Keep your last full backup, move it to another directory for safekeeping. Delete your backup task from within ATI, and create a new task.
I have the same problem. ATI home 2010. I did a full backup of "MyDocuments", choosing the "data backup", and ATI misses 1 folder I created in MyDocuments, named "Downloads", and everything in the folder. I went in ATI settings and made sure NO file types are excluded, and made sure ALL of the folders and files under "MyDocuments" were checked, but ATI still will misses this folder. So, I moved everything out of the folder named "Downloads" and put everything in just "MyDocuments" but ATI still will NOT back those files up. The files are all of different types, some .zip, some documents, etc..
Why is ATI picking and choosing what it wants, and not just backing up ALL files in "MyDocuments"?
(I also tried the same thing using "Incremental", and ATI still misses files.