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“incremental” & “differential” backup usage in Cobain Options · View
sorcerer
Posted: Saturday, June 19, 2010 6:35:49 PM
Rank: Newbie
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Joined: 5/14/2010
Posts: 7
I setup 2 incremental backup tasks – both on timer scheduling. One task backup every 5 minutes; the other task backup every 35 minutes.

Both tasks backup files from a common directory, say “Folder1” to their respective folders.

During the test period, I manually dumped new pdf files into Folder1 every 5 minutes. These pdf files had different timestamp on them.

I started the 2 tasks at the same time. There was a time collision every 35 min. which I did not think about until after the test was underway.

The first 6 incremental “5 min” backups contained pdf files I dumped into “Folder1”

Every 7th “5 min” backup collided with the “35 min” backup. During the 3.5 hours testing period, the “35 min” backup task executed immediately before the “5 min” backup task.

Here are the parts I don’t quite understand:

1/ The “5 min” backup folder that was created right after the “35 min” backup task, was empty. Why is that? The “35 min” task and the “5 min” task are distinct tasks.

2/ The time stamped folders of every “35 min” backup only contained the files which should go into the next “5 min” backup, and then the “5 min’ backup was empty; presumably because the “5 min” task did not detect any change from the previous backup (it referred to the “35 min” backup rather than the previous “5 min” one). I was expecting each of these “35 min” backup folders to contain all the pdf files I dumped into “Folder1” between the current run and the previous run of the “35 min” backup. The “35 min” run executed exactly like the “5 min” run. Why?

3/ I modified the setting of the “35 min” task from incremental to differential during the test. The results were identical. Why?

3/ From the help index of Cobain, it said
Increment backup will check if the source has been changed from last backup.
Differential backup will check if the source has been changed from last FULL backup.

In my test, all “35 min” incremental tasks seemed to respond to the “last backup” from the last “5 min” backup. But these 2 tasks are separate tasks. So what does “last backup” refer to?
The first backup is always a “FULL” backup. I was expecting everything I dumped into “Folder 1” would be copied into the next “35 min” backup run after I changed the setting from incremental to differential. But the task still did not behave in the anticipated manner.

Would someone kindly advise where have I gone wrong in setting up the backup tasks?
Ultimately, I am trying to set up a weekly backup (for long term archive) and daily backup (for emergency use only, and data in daily backup folders will not be kept.) and all the files that need to be backed up are located in the same folder (which I simulated with “Folder1”).
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Posted: Saturday, June 19, 2010 6:35:49 PM
Filbert
Posted: Saturday, June 19, 2010 9:01:20 PM
Rank: Advanced Member
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Joined: 3/13/2008
Posts: 32
If you use more then one task on the same source you will have to uncheck the task option "Use file attribute logic". Then the tasks will use timestamps and it should work. The "archive attribute" is otherwise cleared by the first task and so the second task thinks the file hasn't been changed.

But there might be some other conflicts, eg you can't use the option "Create seperated backups..." if you use timestamps...

Greets, Filbert
sorcerer
Posted: Saturday, June 19, 2010 9:43:15 PM
Rank: Newbie
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Joined: 5/14/2010
Posts: 7
Thanks Filbert.
If I uncheck "Use file attribute logic", the incremental and differential backup methods are no longer available. Under such condition, Cobain only offers FULL backup. I want incremental backup only.
Filbert
Posted: Saturday, June 19, 2010 9:52:03 PM
Rank: Advanced Member
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Joined: 3/13/2008
Posts: 32
As written, there might be other conflicts. Uncheck "Create sepereated backups..." and you can use incremetal backups.

Greets, Filbert
sorcerer
Posted: Saturday, June 19, 2010 10:43:13 PM
Rank: Newbie
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Joined: 5/14/2010
Posts: 7
Hello Filbert,
I unchecked both "Use file attribute logic" & "Create separate backups using timestamps" and am running incremental backups. The result is as expected. Cobian created a folder using the source folder name. After 8 "5 min" run, all files are backup to the same folder incrementally. I guess there is no way I can use time stamp and separate folders at the same time - unless I schedule 6 separate backup tasks (to simulate 6 days)

This is definitely problematic to me. While I can "stomach" all incremental backups shuffled into the same folder for daily backup, I cannot have weekly backup dumped into the same folder. I intended the weekly backups for long term archive and separation of weekly incoming data is extremely important to me.
I am repeating the test now and scheduled the backup to avoid the collision time between the execution of "5 min" and "35 min" runs. See how it goes.

Thanks again for your advises.
Regards,
Sorcerer
Filbert
Posted: Saturday, June 19, 2010 10:53:04 PM
Rank: Advanced Member
Groups: Member

Joined: 3/13/2008
Posts: 32
If I got it right you can still use the "attribute logic" and "seperate backups" for the weekly backup. It just has to be the only task that relies on the attribute logic for this source.

Greets, Filbert
sorcerer
Posted: Sunday, June 20, 2010 9:08:51 PM
Rank: Newbie
Groups: Member

Joined: 5/14/2010
Posts: 7
Hello all,
In between watching the worldcup and experimenting with various backup configuration options/test runs, I observed the following:
1/ Based on the suggestions from Filbert on various configuration settings, user cannot create 2 (or more) different scheduling backup tasks with source file from the same folder (Elaborated below).
2/ Do not try to backup from one destination folder to another destination folder (e.g. in my case backup daily archive folder to weekly archive folder). Cobain will go through an endless recursive backup which cannot be stopped. The resulting multiple subfolder created cannot be deleted. (I had tried using DEL, "Shift+Delete", Unlocker app to no avail.)

Surely, from the feedbacks in the forum, someone must have done daily and weekly backup with data from the same source folder successfully. Can someone kindly share your experience and setup procedures with the forum please?

Regards,
Sorcerer

Note:
To simulate daily & weekly backups in a short period of time, I used timer option in Cobian. I have spaced execution time between successive backups and between “daily” & “weekly” backups so that no backup task can run concurrently (i.e. no collision). I also manually added just 3 pdf files in between each “daily” backup runs. I also understood the granularity of the timer on Cobian does not correspond to the system time (i.e. the exact time of execution) so this had been taken care of in the spacing of execution time between the 2 backup tasks. I have a hard time in understanding the true definition of “last backup” in Cobian. I have 2 completely separate tasks (daily & weekly) acting on the same source folder. It seems to me “last incremental backup” means the last execution of backup regardless of which task Cobian was executing (i.e. regardless the backup is from the same task or a different task). Therefore, when I ran “weekly” incremental backup, I only received files that was dumped (manually) into the source folder just before the weekly backup execution was run. The weekly incremental backup failed consistently to refer itself to the previous weekly backup and referred itself to the last backup run which was the daily backup. The devastating consequence was all the files that were picked by the daily backup task after the first run of the weekly backup task were missing in the second incremental weekly backup run. This behavior replicated itself in subsequent executions of the weekly backup.
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