Shorten the backup process?

Shorten the backup process?

[Chris Lee]

Hi All,
I hope this to bee food for thought as I am not able to code such a thing nor am 
I in need of such a thing but it seemed like a good idea when it struck me, so;
When an filesystem is snap shotted it is a function of the  running filesystem 
to provide the data in that snapshot. (or is that lvms doing?)
Most users who use snapshots for backup are going to mount the snap shot and 
then tar it up.
Would it be a good idea to provide a virtual file through something like the 
sysfs that is a tar representation of the snapshot so that a backup can just 
copy the tar file off as needed?

Thanks for reading,

Regards,
Chris.

Re: Shorten the backup process?

[Greg Freemyer]

On Sat, Oct 9, 2010 at 4:35 PM, Chris Lee <cslee-list@cybericom.co.uk> wrote:
>
> Hi All,
> I hope this to bee food for thought as I am not able to code such a thing nor am I in need of such a thing but it seemed like a good idea when it struck me, so;
> When an filesystem is snap shotted it is a function of the  running filesystem to provide the data in that snapshot. (or is that lvms doing?)
> Most users who use snapshots for backup are going to mount the snap shot and then tar it up.
> Would it be a good idea to provide a virtual file through something like the sysfs that is a tar representation of the snapshot so that a backup can just copy the tar file off as needed?
>
> Thanks for reading,
>
> Regards,
> Chris.

That seems like an overly specialized feature for the kernel.

And even if it were a good idea conceptually:

1) ext4 does not currently offer filesystem snapshot capability.  It
is handled at a lower level in the block stack.  (ie. either in the
hardware array or via device mapper).

2) Those lower levels simply are aware of blocks / sectors, not files.
 Thus they have no ability to create a "tar" file.

fyi: btrfs is a more integrated filesystem, so it is at least
technically feasible with it.

Greg


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