ZFS backups: retrieving a few files?

[Mike Tancsa]

On 11/22/2010 8:29 PM, David Magda wrote:
> On Nov 22, 2010, at 17:13, Andrew Reilly wrote:
> 
>>> The currently accepted practice is to create a ZFS file system on the
>>> backup drive and just keep sending incremental snapshots to it.  As long
>>> as the backup drive and host system have a snapshot in common you can do
>>> incremental transfers.  This way you only have to keep the most recent
>>> snapshot on the main system and can keep as many as you have space for
>>> on the backup drive.  You also have direct access to any backed up
>>> version of every file.
>>
>> That sounds like a very cool notion.  Not unlike the
>> time-machine scheme.  Interesting how different capabilities
>> require going back and re-thinking the problem, rather than just
>> trying to implement the old solution with the new tools.
> 
> As noted, saving the output of "zfs send" isn't very useful and
> generally not recommended as  a backup mechanism. It's come up quite
> often on Sun/Oracle's zfs-discuss list:
> 
>     http://www.google.com/search?q=zfs+send/receive+as+backup+tool
> 
> In addition to regular snapshots, also make sure to have an offline
> backup of some kind (tar, Networker, NetBackup, Amanada, etc.). Errors
> can propagate to online copies / backups, and if an intruder can
> penetrate your primary system, there's a good chance they can get to the
> secondary copy of your data; penetrating a tape on a shelf over the
> network would be much more challenging. :)

I am still trying to figure out the best way to do zfs backups locally
here for rollbacks as well as DR. I was looking at some of the
techniques at

http://www.cuddletech.com/blog/pivot/entry.php?id=984

But thats outdated ?  WRT errors in the file, perhaps PAR* tools can
overcome some of these issues if you are dumping to a file on tape

*/usr/ports/archivers/par2cmdline

	---Mike