Re: Some help with dd backing up into an iso
- Date: Wed, 8 Mar 2017 12:17:44 -0600
- From: David Wright <deblis@xxxxxxxxxxxxxxxxx>
- Subject: Re: Some help with dd backing up into an iso
On Wed 08 Mar 2017 at 16:29:00 (+0000), GiaThnYgeia wrote:
> Hello, this is OP speaking :)
> My use is about 96% backing up the image and only when things fall apart
> will there be a restoring attempt. But what good would saving multiple
> successive images be if none can be ever restored?
This is the nature of backups. Careful people make backups and test
them for integrity. The next thing they typically do with the backup
devices (sticks, drives, tapes, etc) is use them the same way at a
later date. Most backups are never restored; they just go through an
endless rotation of being grandfather, father, son, grandfather…
> >> Yes, yes, this is back to the technical details of making copies.
> > But we are on computers. Technical details matter.
Yes they do, but my point was that others, more qualified, were
discussing the tactics of making copies, and my comment was only about
the strategy: the futility of copying A to B (in a process described
as "backing up") and, without any checking (or any other pressing
need) copying B back over A, thereby _potentially_ losing the
integrity of both.
> >>> UPS
> >> ...which cost EUR...?
> I have one on my main personal system and it I can make UPSs better than
> those in the market for less. I do see the point, if power fails
> through the dd process the image is junk, but the USB didn't fail, it
> just gets backed up when the good power people decide to send juice
> again. I can live without the PC, my fish will not survive without
> aeration for too long and I am too lazy or may be away to feed them with
> aerated water.
OK, I now get the point that your original post really just described
your exercising a few tools with stuff that was at hand, and that the
1.7GB of data was just something that happened to be on the device.
What validity was being tested, I'm still not sure of.
I apologise for reading the post as a "real world" situation where
the said data carried some value. People on this list running some
systems would risk the sack if they backed up a device and then
immediately overwrote it with the backup, whether or not they were
familiar with the finer details of dd, cp etc.