Linode.com Forum

mpoly · Senior Newbie Joined: 10 Apr 2004 Posts: 15

I'd like to see two buttons, under each disk image: Download and Upload.

The goal is to allow one to save an image off-site and restore it at will. When a linode gets so hosed that rsync is not an option, this can be a lifesaver.

Downloaded bytes can count against the linode's limit if that's an issue. Compression would be a plus, but not a must.

Cheers,

Michael

erik.elmore · Junior Member Joined: 17 Apr 2005 Posts: 45

I have a small monolithic filesystem with debian on it that I can boot into for making backup tarballs and then restoring them. Works really well for me.

Internat · Posted: Tue Sep 06, 2005 7:41 pm Post subject:

i think that function would be good.. id like to be able to download my entire partition and then be able to upload it later on.. tho i an see issues with bandwidth and stuff but thats another concern

mpoly · Senior Newbie Joined: 10 Apr 2004 Posts: 15

Bandwidth is certainly an issue; counting such up/downloads against the linode's limit is the fair and simple way to handle it...

The problem with tar is that you need free space for the temp OS and for the huge tarball...

m

erik.elmore · Junior Member Joined: 17 Apr 2005 Posts: 45

I say again, I boot into a very small debian image to make backup tarballs--the interesting implications there, in case you don't see them are: Tarball backups can be customized to only backup what you want and compressed to save space and bandwidth... everybody wins.

bpendleton · Junior Member Joined: 10 Oct 2003 Posts: 25

Of course, conversely, you have to reboot in to get such a feature. If the linode control panel had support for downloading disk images, you could do that while your linode is still running.

However, this should really be an advanced feature, since things quickly get complicated. To make usefully consistent backups with the linode booted, for instance, the filesystem would need to be remounted read-only in your linode before downloading... but there's probably no way to check for this from the control panel. Thus, many users would be likely to get it wrong, and thus have corrupt, if not useless, backups.

I have seen that some other providers use LVM for this. I have LVM setup *inside* my Linode, and can make snapshots, then backup the snapshot, once created. That, though, is even more complicated to get right than remounting your filesystem read only for control panel backups.

erik.elmore · Junior Member Joined: 17 Apr 2005 Posts: 45

To clarify... You would not have to reboot to make a tarball of your running system, nor to restore from a tarball--perhaps you might if you were doing a full restore, you can still restore parts of your system via tarballs without any downtime. You would have to take the filesystem completely offline to make an image of it or to restore it, and you cannot very effectively restore a partial disk image. I really only ever have to boot into debian for doing a full restore from backup where my system no longer runs anyway.

disk image download really isn't a very good way to go at all...

mpoly · Senior Newbie Joined: 10 Apr 2004 Posts: 15

I agree that for partial/incremental backups, tar or rsync are a better option, but this feature would be useful for those occasions when one wants to backup everything.

For example, I want to try an upgrade to FC4, but I just know something will go wrong the first time. No problem, if I could just restore the partition from an off-site backup. It is on occasions like this that one would use the feature.

The "Duplicate an existing Disk Image" already checks whether a disk is mounted or not. The same restrictions that apply for "Duplicate" should apply here...

Cheers,

m

erik.elmore · Junior Member Joined: 17 Apr 2005 Posts: 45

When I say partial, I'm not really talking about a partial backup. What I mean is that its not a good idea to use disk images for backups. A "full" backup doesn't mean that it has to back up every file or the entire filesystem image. A 9 gigabyte filesystem image is 9 gigabytes, even if you only have 200 megabytes used--what use is it to copy everything else?

There just isn't a place for this kind of backup/restore mechanism. It is just a way for lazy admins to cause more frivilous disk access and performance hits.

The duplicate disk image feature has its uses, but remote backup is *not* one of them.

[edit]

and before someone cites Norton Ghost, let me point out that Norton Ghost doesn't make "images", it does a very intelligent backup of certain files selectively. For example, it doesn't back up swap files at all.

sednet · Posted: Tue Sep 13, 2005 8:12 am Post subject: Remote Backups

erik.elmore might not like this idea but I think it could be useful.

It would be nice to take down my linode and rsync the disk images every month. Then if my linode gets hacked or I break it I could just rsync the other way and have a working system in no time at all. Doing this with anything but rsync would be very wasteful. This would hammer the disks, but not that much more than tripwire on full firesystems.

This is nothing that can't be done with a minimal debian boot setup anyway.

NecroBones · Posted: Tue Sep 13, 2005 10:06 am Post subject:

I agree, rsync is a great way to do this. That way you only copy out the changes.

Personally, what I do for mine is periodically rsync (or tar.gz in some instances) only the hard-to-replace files, such as the contents of /etc, /root, /home, /var/spool/cron, etc. Most of everything else is recoverable with a fresh OS install.

This keeps the bandwidth usage low, and doesn't call for any new capabilities.
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Ed/Bones.

cxxguy · Newbie Joined: 03 Sep 2005 Posts: 4

ssh mydomain.com dd if=/dev/disk/whatever | dd of=whatever.backup

Xan · Posted: Sun Sep 18, 2005 9:34 pm Post subject: Re: it's in there (like prego)

sednet · Posted: Mon Sep 19, 2005 9:52 am Post subject: Re: it's in there (like prego)