rsnapshot not doing hardlink

[jbao605]

Below are the related rsnapshot.conf section:

Model: ReadyNAS Duo [X-RAID]
Firmware: RAIDiator 4.1.16 [1.00a043] 
Memory: 256 MB [2.5-3-3-7]
rsnapshot.conf version 1.2
rsync  version 3.0.9  protocol version 30

For some reason, rsnapshot seems to be creating backup without creating hard link, rather, it creates new copy of files between the source and the backup, though between different versions of the backup (hourly.0, daily.0 etc), it seems to be same hard link. Here is the rsync command and parameters after I enable verbose output from rsnapshot:

/usr/bin/rsync -av --delete --numeric-ids --relative --delete-excluded \
    /c/backup /c/snapshot/hourly.0/localhost/

interval        hourly  4
interval        daily   3
interval        weekly  3
interval        monthly 10
interval        yearly  1

backup  /c/backup/      localhost/      rsync_short_args=-av

Any suggestion?

Thanks

[Marc_V]

Hi @jbao605

Welcome to the Community!

Do you want to create Hard link? Hard links are created in the back end so this is technically not supported.

If you want for hard links to be preserved you need -H, not sure though if this version of rsync will have it supported but it might.

Other users might have input on this inquiry as well.

Regards

[jbao605]

I want the backup to be done via hardlink, which will save space, not to preserve hardlink, though I don't see why that cannot be done.

My understanding that the purpose of using rsync to backup is to be able to create hardlink instead of physical copy of the source, so that the backup does not take up extra space to store another copy. But my observation is that it does another copy instead of hardlink, and only hardlink between different version of the backup, not between the backup and the source.

Thanks

[StephenB]

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@jbao605 wrote:

My understanding that the purpose of using rsync to backup is to be able to create hardlink instead of physical copy of the source,

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A hardlink doesn't give you a backup, it is another link that goes to the same physical datablocks..  If those blocks are corrupted, the link is worthless.  So what's the point?

I run rsync to make a real backup - another copy of my data on a different device.

[jbao605]

@StephenB You made a very valid point. I was trying to save some more space because all my data on NAS is already a backup of copy from the actual data on computer hard drives, and my readyNAS drive has a XRAID 2 disk setup. Guess I will have to use twice of the space for backup done by rsnapshot.

Thanks