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Continue on errors option leads to full backup

Asked by mdalo

Hi all,

I am using backintime on a 'cifs' network drive. I get some rsync errors : symlink will not copy, permission is denied for some files, also some mknod and mkstemp errors (I don't know what this is)... I don't really care about these errors, because the files concerned are not really important for me. So I have checked the "Continue on errors" option.

Everything is going well then. I have backups with the note "WITH ERRORS!". But I noticed that every backup made are full backup. I mean, even if I don't change anything to my computer, everything will be transfered again on my device. So it takes time and it takes a big place on the hard drive, which is not the purpose of backintime. Any idea on what could be the reason for this issue ?

Thanks for your help.

Here is the fstab line for the backup drive
//Drive/Data/ /media/Data cifs rw,user,gid=100,uid=1000,credentials=/home/.credentials,noserverino,iocharset=utf8,file_mode=0777,dir_mode=0777,_netdev 0 0

Here are 4 examples of rsync errors (I replaced filenames with ...)
[E] Error: rsync: send_files failed to open "...": Permission denied (13)
[E] Error: rsync: symlink "..." -> "" failed: Operation not supported (95)
[E] Error: rsync: mknod "..." failed: Operation not permitted (1)
[E] Error: rsync: mkstemp "..." failed: No such file or directory (2)

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Dan (danleweb) said : 		#1

If you have error (nodes, symlinks, ...) then this means that the snapshot is not a real copy of the included items so BIT will try to make a new snapshot.

The best thing to do is to exclude everything makes errors since you don't care (and include only what you really need). For example nodes are usually in /dev and are created dynamically. Why do you what to backup this items ?

I don't know if cifs support sym-links and hard-links.
Hard-links are used between snapshots for unchanged files. This is very useful to save disk space. If cifs don't support them (and I don't thing they do) then the same file will be copied again and again and it will fill you disk space (and the process will be slower).

Can you mount it with another network file system ?

Regards,
Dan

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mdalo (mayel-dalo) said : 		#2

Hi Dan,

Well the disk is an apple time capsule. Except me, people use apple here at work. I have looked on the web and I think cifs is the only file system that I can use. AFS is not officially supported and I am not sure that it would resolve the problem.

It seems that cifs does not support symlink. I haven't found a way to tell BIT to ignore symlink. Does this option exists?

For the other errors, I will try to figure out how to get rid of them but it does not seem to be an easy task.

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Dan (danleweb) said : 		#3

You ca try this:
http://www.omgubuntu.co.uk/2010/11/connecting-to-your-apple-time-capsule-in-ubuntu/

Regards,
Dan

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mdalo (mayel-dalo) said : 		#4

I tried that already.

Unfortunately, it messed up the capsule. I don't know why. I had to reset the drive afterwards. Thanks for suggesting though.

To reply to your previous post. I didn't backed up the /dev folder. There are some docs in the hidden files of my home directory that generates mknod error, same for mkstemp.

The biggest number of errors are due to symlink though. There are no options at the moment to ignore symlink in BIT right? There is one to make hard copy of the links but not to ignore them, correct me if I am wrong.

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mdalo (mayel-dalo) said : 		#5

"--safe-links"

I just saw this option for rsync but I am not sure that this will exclude all the links since it only excludes links that are outside the tree or absolute links.

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Dan (danleweb) said : 		#6

In Settings => Expert options tab you have:
1. copy safe-links (it use --safe-links)
2. copy links (copy real files not the links)

And you are right, for now you can't exclude links.
Does cifs support hard-links ? If not as I said you will waste a lot of disk space (since there will be a full copy of the file in each snapshots).

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paulatz (justforspam) said : 		#7

I've tried for a long time to have backintime work on a cifs filesystem on ubuntu, but I have experienced the same problem as you which in the end forced me to give up.

After some testing I found out that the real cause in not a problem in backintime but some very difficult to reproduce bug with the cifs filesystem kernel module. When the cifs filesystem is used internsively, to create many files and/or copy a lot of data (it is not clear to me) it will eventually stop allowing the creation of new hardlinks until it is restarted (a full unload/reload of the module is necessary, just unmount/mount won't work). When this happens ,attempting to create an hardlink (with any mean) will just give a cryptic input/output error.

Unfortunately I have not (yet?) been able to reproduce it reliably and, afaik, it may depends on a bad client as well a bad server so I did not bother to report it.

Can you help with this problem?

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