Is there any difference between the two following strategies for backing up files to a remote system:-
1 Mount the remote destination directory using sshfs/fuser Copy the files to the 'local' directory just mounted using rsync, rdiff-backup or whatever.
2 Copy the files directly to the remote system using rsync or rdiff-backup.
Strategy 1 has the significant advantage that the remote system doesn't have to have anything other than ssh available. You don't run into any issues with mismatched versions of rdiff-backup or anything like that. Both strategies require that you set up some form of 'passwordless' login to the remote system or you need to enter the password (or passphrase) when the backup is run.
I was thinking that I can run either of these from my .xprofile so that by the time they are run the required passphrase has been entered.
I was even thinking that I could run the backup to one remote system from my wife's desktop .xprofile and to the other from my desktop .xprofile so they'd be at different times and to different remote systems, most unlikely to get both damaged at the same time.
Only someone breaking into my working X environment would get access to the backups, just breaking into my home systems wouldn't do it. They might of course break into the remote systems I use for backup but then I have my home backups that haven't been compromised.
Chris G wrote:
Is there any difference between the two following strategies for backing up files to a remote system:-
1 Mount the remote destination directory using sshfs/fuser Copy the files to the 'local' directory just mounted using rsync, rdiff-backup or whatever.
2 Copy the files directly to the remote system using rsync or rdiff-backup.
I think if you run as per option 1 then you will lose most of the bandwidth saving and speed benefits of rsync because it will be trying to compute the checksums for the remote files locally rather than on the remote machine as intended.
That said rsync will (with the default flags set) not bother computing checksums for files that have identical timestamps on the local and remote systems so it would still probably be quicker than copying everything each time.
On Tue, Dec 22, 2009 at 09:39:51PM +0000, Wayne Stallwood wrote:
Chris G wrote:
Is there any difference between the two following strategies for backing up files to a remote system:-
1 Mount the remote destination directory using sshfs/fuser Copy the files to the 'local' directory just mounted using rsync, rdiff-backup or whatever.
2 Copy the files directly to the remote system using rsync or rdiff-backup.
I think if you run as per option 1 then you will lose most of the bandwidth saving and speed benefits of rsync because it will be trying to compute the checksums for the remote files locally rather than on the remote machine as intended.
That said rsync will (with the default flags set) not bother computing checksums for files that have identical timestamps on the local and remote systems so it would still probably be quicker than copying everything each time.
That's an efficiency point I hadn't thought about, I guess the same will apply to rdiff-backup (which uses a similar strategy to rsync).
Thanks for the feedback.
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Chris G wrote:
Is there any difference between the two following strategies for backing up files to a remote system:-
1 Mount the remote destination directory using sshfs/fuser Copy the files to the 'local' directory just mounted using rsync, rdiff-backup or whatever.
2 Copy the files directly to the remote system using rsync or rdiff-backup.
My concern with option 1 is that sshfs falls over a little too often for me to trust it with an unattended backup. I'd rsync if I could.
Hope that helps,
On Tue, 2009-12-22 at 21:20 +0000, Chris G wrote:
Is there any difference between the two following strategies for backing up files to a remote system:-
1 Mount the remote destination directory using sshfs/fuser Copy the files to the 'local' directory just mounted using rsync, rdiff-backup or whatever.
2 Copy the files directly to the remote system using rsync or rdiff-backup.
I would expect option two to have better performance when doing a backup in the same way that FTP will usually transfer a file faster then NFS. This is because at application protocol level there are fewer points where the sending end must wait for the receiver - when streaming the data this is handled at TCP level which has a transmit window etc.
Of course option one may have other uses that make it attractive.
Regards, Steve.
On Wed, Dec 30, 2009 at 08:01:33PM +0000, Steve Fosdick wrote:
On Tue, 2009-12-22 at 21:20 +0000, Chris G wrote:
Is there any difference between the two following strategies for backing up files to a remote system:-
1 Mount the remote destination directory using sshfs/fuser Copy the files to the 'local' directory just mounted using rsync, rdiff-backup or whatever.
2 Copy the files directly to the remote system using rsync or rdiff-backup.
I would expect option two to have better performance when doing a backup in the same way that FTP will usually transfer a file faster then NFS. This is because at application protocol level there are fewer points where the sending end must wait for the receiver - when streaming the data this is handled at TCP level which has a transmit window etc.
Of course option one may have other uses that make it attractive.
Speed is actually not very important as, after the first pass (using rsync or rdiff-backup) only changes are sent so not a huge amount of data crosses the interface.
I've actually decided on yet another strategy (?!) :-
Add some disk space to my 'always on' server system.
Copy file systems to be backed up from various clients to the new backup area on the always on server disk. This can be done with an anacron script in /etc/cron.daily so it will work from systems that are only turned on intermittently - i.e. desktop computers.
Run a 'pull' rdiff-backup on the *real* backup system in the garage from the backup area on the 'always on' server.
This means I can make the garage backup system very secure (in terms of break in from the internet), I could in fact make it inaccessible from outside and it could still do the backups. The 'always on' server is the least secure system as it is the one that is accesible from the internet but even if someone broke into it and destroyed everything it wouldn't affect the incremental backups on the garage system.
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Chris G -
MJ Ray -
Steve Fosdick -
Wayne Stallwood