How to write schedule for differential backups SOLVED !!
Hi; 09/29/09 - See my post below - I believe it's the solution!!
Referencing post 1536: Difference between Incremental and Differential Backup
I have a full backup scheduled for each Saturday of the month and the .tib is written to it's own folder (Sat1, Sat2 etc.) I also have differentials scheduled to match each full backup. However, the differentials appear to be just as large as the full backups and my Tuesday overwrites Monday, Wednesday overwrites Tuesday etc.
Do I need to create a series of one day differentials so they don't overwrite each other or isn't the differential supposed to know what day it's on and adjust the filename to prevent overwriting?
In my Saturday1 folder I'm expecting to see the following after a week of backups:
Saturday1_full_backup
Monday_diff_1 , Tuesday_diff_1, Wednesday_diff_1, Thursday_diff_1 and Friday_diff_1
But what I got was the Saturday1_full_backup and one differential backup. Both files are exactly the same size.
Thanks in advance for help with getting this scheudle straightened out.
Robert
1. Incremental type backups versus Differential type backups
Each incremental backup is dependant upon the prior one being good. If one backup archive becomes corrupt, then all backup files after that are useless.
A differential backup contains all the changes from the original backup so each differential needs only the original to function. For example, if on day 25, you wish to do a restore of your system, using the incremental method you would need to have the original backup plus the 25 prior incremental--all in good condition. If you were using the differential method, you would only need to use the original plus any one single day within the 25 day grouping. Using fewer backup archives reduces the changes of something going wrong.
As part of your ongoing file integrity, you would want to validate each days backup. When validating an incremental backup, Acronis needs to have the master and all preceding incremental backups. So again, on day 25, Acronis would validate the master plus the 25 incrementals. If one does not validate, the entire set is useless. With the differentials, it needs the master plus the one single day being restored and both must be validated.
When restoring, the master or orignal backup must be within the folder where the other backup files to be used are stored. In other words, the whole group of backup becomes a set.
If you move any of the files, it is recommended that the moved files are again validated.
I would include the master or original backup in any move of incremental backup files. Without the master, the incremental files are of no use.
2. The differential backup size is controlled by the amount of data that has changed from the last full backup. If the drive was defragged after the original, this would cause the differential to be really large since all the data has changed positions.
3. One cause of the old files being removed might be the task setting in the "backup method" where the delete old files might be checkmarked.
4. The second full backup is the same name as the first full backup so the first one will be overwritten. Two files cannot exist with the same name.
5. A batch file can be easily constructed to save your all your files so none are overwritten. If you wish assistance with this, let us know via your response. Where are you storing your backup archives?
I think I found the solution!!
Jerry F. and GroverH - thanks for the replies. I tried a lot of tests to understand what was going on and found that I started out wrong and it led to no differential backups.
When I started setting up my backup schedules for full and differentials I wrote every scheduled backup at one time. This is incorrect! Even though you have schedules marked as differential the backup still creates a full backup because it can not find a "previous full backup". This is/was not very clear in the instructions or help file or anywhere I looked. Sorry Acronis, but it was not explained very well and maybe something needs to be done with the interface when differential is selected to force picking the correct choices. Perhaps picking differential first and then force the user to pick the full backup filename and not let them put in their own filename.
So, what's right? Schedule a full image backup and either run it or let it run on schedule. After a successful full backup write your schedule for the differential. The trick is to select the name of the full backup when asked for Backup Archive Location. And then select differential when asked for backup mode. Here are the steps:
1. Select the Create and schedule a new task icon. Click next.
2. Click radio button for entire disk contents. Click next.
3. Select the disk / partition you want to backup. Click next.
4. Here is where you are asked for Backup Archive Location. Select the name of the full backup that you just created. Click next.
5. Select the radio button for Create Differential backup archive. Click next.
6. Do all the steps for passwords, backup options and Archive Comments. Click Next.
7. Select the radio button for how often you want the differential to run. (I selected Weekly). Click Next.
8. Select your time and select the days you want the schedule to run. (I selected Monday through Friday) Click next.
9. Enter the username and password. Click next
10. Click Finish.
I ran my backup for the differential and it created a backup that had a "2" appended to the end of the filename used for the original full backup. The next time it runs it will append a 3, etc. The size of the differential is now 411 KB. and the full was 63,000,000 KB. Big difference!
Like I said, I think this is the solution. I have not tried a restore yet, but I believe that this is correct and a restore should work as advertised. We all will appreciate comments and corrections if my understanding and steps are not correct. I mean we want it to work correctly.
Thanks,
Robert