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DAR Backups Incrementals Question

Offline Mirfster

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DAR Backups Incrementals Question
« on: May 27, 2016, 05:25:11 PM »
Sorry if this is clearly stated somewhere (I did check the "Backup with dar" wiki first) but am unclear.

Are the incremental backups based solely on the full or do they take into account the last incremental?

For example say I have it set for 1 Set and 28 increments:
Initial full backup runs and it is 100 GB
Day 1 comes - There is 1 GB of changes, so Inc#1 is 1 GB
Day 2 comes - There are not any changes, so what size is Inc#2?
Is Inc#2 1 GB (based on just the Full) or 0 based on Full + Inc#1?

Reason I am asking is I have been seeing incremental backups consuming 24 GB a day on a system that contains ~ 700 GB.  I just can't phatom that they are changing 24 GBs worth of files a day.

Thanks in advance and sorry if this is already clearly posted/explained already.

Offline TerryF

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Re: DAR Backups Incrementals Question
« Reply #1 on: May 27, 2016, 07:03:46 PM »
As I understand it:

An incremental backup is one that provides a backup of files that have changed or are new since the last incremental backup
--
qui scribit bis legit

Offline Jean-Philippe Pialasse

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Re: DAR Backups Incrementals Question
« Reply #2 on: May 27, 2016, 08:08:58 PM »
Reason I am asking is I have been seeing incremental backups consuming 24 GB a day on a system that contains ~ 700 GB.  I just can't phatom that they are changing 24 GBs worth of files a day.
.

I am not familiar with dar in particuliar, but it is easy to have a  backup seing 24 go of files changing or being erased and created.. Just rename the base directory. If the alrythm is simple it will only see 24 gb erased, 24 gd added, and backup the 24 gb.

 More evolved algorithm will check for this, and also for identical files that could be hardlinked to save space.

Offline Mirfster

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Re: DAR Backups Incrementals Question
« Reply #3 on: May 27, 2016, 08:15:42 PM »
K, I will investigate a bit more.  AFFA is looking better and better at the moment.  :)

Offline Mirfster

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Re: DAR Backups Incrementals Question
« Reply #4 on: May 27, 2016, 08:19:47 PM »
Oh side note:  I just realized that my "Silver Supporter" disappeared? However I just checked PayPal and the normal reoccurring donation was just sent out on the 25th.  Did I miss something?

Offline brianr

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Re: DAR Backups Incrementals Question
« Reply #5 on: May 28, 2016, 11:37:30 AM »
As I understand it:

An incremental backup is one that provides a backup of files that have changed or are new since the last incremental backup

and that (I am pretty sure) is how dar works
Brian j Read
(retired, for a second time, still got 2 installations though)
The instrument I am playing is my favourite Melodeon.
.........

Offline Stefano

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Re: DAR Backups Incrementals Question
« Reply #6 on: May 28, 2016, 11:57:44 AM »
Oh side note:  I just realized that my "Silver Supporter" disappeared? However I just checked PayPal and the normal reoccurring donation was just sent out on the 25th.  Did I miss something?

we're checking, will get in touch with you off line asap, thank you for reporting

Offline Mirfster

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Re: DAR Backups Incrementals Question
« Reply #7 on: May 29, 2016, 09:11:27 AM »
Thanks, I have sent pertinent information to Jean-Philippe Pialasse.