Posted on 2011-04-21
I am having a bad Rsync issue and while I am pretty sure I know the answer (ie I'm screwed) I wanted to bounce if off the experts first.
I started using a D2D backup solution with a local readynas as the backup target.
Everything worked great for the first month and then everything has fallen apart. I thought the backup worked a bit differently and I think that assumption has caused my solution to be a failure.
The way the backup works is that each day it creates a new folder, well a number of folders, but only one is important due to it having the actual data files (the bulk of the data). So the files are structured as:
Inside each one of these folders is a file containing the backed up data for the drive. Each filename is the same such as:
The problem is once you reach the maximum number of restore points.
What happens at this point is that the oldest full backup is merged into the incremental. So for the example above the .D2D file in S00001 is merged with the .D2D in S0002
Then this merged file is saved ins S00002 and S00001 is purged. This continueS each day.
The problem then is that Rsync sees the file in S00002 as the incremental + FUll, rather than Full + incremental.
So for example if my file in S00001 was 14GB, and the incremental in S00002 was 1GG, the merged file according to Rsync is 14GB of changed bits rather than the reverse.
The end result is that after 30 days of backups, Rsync is basically trying to sync a full backup every night, and bogs down.
I am assuming there is probably nothing I can do about this, but am hoping I am wrong.