Does Acronis True Image Home 2011 stores some recovery records ?

[Castor Nageur]

Hi all,

I am actually trying Acronis TIH 2011.

* But because a backup is a very sensible file, do you know if TIH
stores some recovery records like WinRAR does or like you can do
externally with QuickPAR?

Thanks to these records, you can recover a corrupted archive.
I searched in the Acronis manuals and in the software settings but did
not find anything like this.

Thanks in advance if you can provide some more information.

 

[Arno]

Hi all,

I am actually trying Acronis TIH 2011.

* But because a backup is a very sensible file, do you know if TIH
stores some recovery records like WinRAR does or like you can do
externally with QuickPAR?

Thanks to these records, you can recover a corrupted archive.
I searched in the Acronis manuals and in the software settings but did
not find anything like this.

Thanks in advance if you can provide some more information.

What is the issue? If you are concerned your backup can be
accesses by people that shopuld not, you shpuld not put
any plaintext data in there in the first place. One apporahc
is to use an encrypted container and back it up in encrypted
form. Look for example at the free and excellent Truecrypt
for that.

Arno

 

[Castor Nageur]

What is the issue? If you are concerned your backup can be
accesses by people that shopuld not

No I am not concerned by other people accesses my backup (anyway,
Acronis already has an encryption option for this), I was asking if a
corrupted archive can be recovered using redundancy bits (stored in
recovery records).
Corruption already happened to me when sectors of my hard disk became
unreadable because of a mechanical problem.
Of course I changed my hard disk and thanks to the recovery records
stored in my RAR files, I was able to rebuild my RAR files which had
some data stored in the unreadable sectors.

I was just asking if Acronis True Image Home 2011 was implementing
such a feature or not ?

 

[Arno]

No I am not concerned by other people accesses my backup (anyway,
Acronis already has an encryption option for this), I was asking if a
corrupted archive can be recovered using redundancy bits (stored in
recovery records).
Corruption already happened to me when sectors of my hard disk became
unreadable because of a mechanical problem.
Of course I changed my hard disk and thanks to the recovery records
stored in my RAR files, I was able to rebuild my RAR files which had
some data stored in the unreadable sectors.

I was just asking if Acronis True Image Home 2011 was implementing
such a feature or not ?

No idea. But keep in mind that error correction coding allways
has hard limits on what it can do.

Arno

 

[Rod Speed]

Castor Nageur wrote

No I am not concerned by other people accesses my backup (anyway,
Acronis already has an encryption option for this), I was asking if a
corrupted archive can be recovered using redundancy bits (stored in
recovery records).

Corruption already happened to me when sectors of my hard
disk became unreadable because of a mechanical problem.

Sounds like you backed up to the same physical drive.

Thats a very unsatisfactory way to do backups.

Of course I changed my hard disk and thanks to the recovery
records stored in my RAR files, I was able to rebuild my RAR
files which had some data stored in the unreadable sectors.

I was just asking if Acronis True Image Home 2011
was implementing such a feature or not ?

The obvious alternative is more than one backup to more than one physical drive.

 

[Castor Nageur]

No idea. But keep in mind that error correction coding allways
has hard limits on what it can do.

QuickPAR can recover up to 10% of any piece of data located anywhere
of your corrupted file.
Imagine, you saved an archive on a DVD, forgot it and stored it in bad
conditions.
If you retrieve it damaged years later, you will still be able to
recover your data (if no more than 10% of your data was damaged).

Obviously, I can not imagine generating some QuickPAR redundancy files
on my 100 GB Acronis backups because it would take an entire day. The
idea was Acronis could do it on the fly (like WinRAR does) but I do
not think it does it.

 

[DevilsPGD]

In message
<0ce5fa3e-a630-4620-9c96-036b68edc82d@o10g2000vbg.googlegroups.com>

QuickPAR can recover up to 10% of any piece of data located anywhere
of your corrupted file.

10% isn't a hard number either, you can recover up to whatever
percentage of data you want based on the amount of PAR2 blocks you
created in the first place.

Nothing stops you from creating 100% PAR2 blocks and throwing away the
entire original media.

Also, even if you set the threshold at 10%, you can't necessarily throw
away 10% of the original media. You can throw away or damage 10% of the
blocks of the original media, but you couldn't damage 10% of every block
and recover.

This difference is mostly academic since damage will often be grouped
together, but it's worth considering if your fear is long-term bitrot.

Imagine, you saved an archive on a DVD, forgot it and stored it in bad
conditions.
If you retrieve it damaged years later, you will still be able to
recover your data (if no more than 10% of your data was damaged).

Obviously, I can not imagine generating some QuickPAR redundancy files
on my 100 GB Acronis backups because it would take an entire day. The
idea was Acronis could do it on the fly (like WinRAR does) but I do
not think it does it.

I'm not sure why your imagination precludes letting a computer run for
several hours at once, but it's entirely possible, it just takes a
while.

QuickPAR takes a long time because the math is complex (it's CPU-bound),
and the fact that it runs after the fact vs during the original backup
wouldn't make much difference in terms of the total runtime. There are
other algorithms that might be more efficient on CPU resources, but few
that offer the redundancy that PAR2 does.

 

[Mike Tomlinson]

What is the issue?

I think he's concerned that a TrueImage archive may become inaccessible
if it becomes damaged, and is asking if tools exist to extract files
from a damaged or corrupted TI archive.

This is one of the problems with backup and proprietary image/archive
files. I use a utility (QuickShadow) which stores backup files
normally, i.e. they're accessible without QuickShadow installed.

 

[Mike Tomlinson]

The program seems to only backup file files. In particular
Windows Registry and the information that the restored file has
to be in a particular location is not retained. Thus, one would
still need at least an image backup program to be able to restore
a Windows system

Yes. QuickShadow is produced with simplicity in mind. As you say, it's
a file backup utility, not a system imager. Once nice feature is that
it monitors file changes and additions and backs these up almost as soon
as they are created or modified.

It does what I want - hassle-free backup to a NAS in another location
over the LAN. Anyone posting here will know that once backup becomes a
chore, it doesn't get done.

I emailed the author with a couple of suggestions and had a positive
reply. As soon as he releases a version that implements those features
I'll be registering and paying for my copy.

 

[Castor Nageur]

Sounds like you backed up to the same physical drive.

No I did not. I used to storing my RAR archives (I was using WinRAR before
Acronis) on a different disk. The archive disk had a mechanical problem so
some sectors became unaccessible so my archives were corrupted.
I was not using WinRAR or QuickPAR recovery records at this time so I was
unable to restore my archive.
Fortunately, my original files were OK !

 

[Castor Nageur]

Not exactly. I don't mind if I need Acronis or some other proprietary
software to read my archive. I just want to be able to restore the archive
like it was before it was corrupted using redundancy information.
I know WinRAR or QuickPAR can handle this so I was asking if Acronis TI
could do it on the fly but apparently not.

 

[Arno]

Mark F <[email protected]> ?crivait

Not exactly. I don't mind if I need Acronis or some other proprietary
software to read my archive. I just want to be able to restore the archive
like it was before it was corrupted using redundancy information.
I know WinRAR or QuickPAR can handle this so I was asking if Acronis TI
could do it on the fly but apparently not.

The standard way to deal with this is to
a) do a complete verify after backup (i.e. a compare)
and
b) have several media sets for the backup

The problem is that unreadable sectors are not much more common
than disks dying outright (in which case ECC does not help at all).
Also, if you run long SMART selftests (i.e. surface scans)
on you disks from time to time as maintenance procedure, the
probability of unreadable sectors drops dramatically.

Arno

 

[Rod Speed]

Castor Nageur wrote

Rod Speed (e-mail address removed) wrote

No I did not. I used to storing my RAR archives (I was using WinRAR before
Acronis) on a different disk. The archive disk had a mechanical problem so
some sectors became unaccessible so my archives were corrupted.

I was not using WinRAR or QuickPAR recovery records
at this time so I was unable to restore my archive.
Fortunately, my original files were OK !

So there was no problem with a corrupted archive.

The obvious way to deal with archive corruption is to have more than one image.

Thats VERY basic backup proceedure and works a lot better than any other approach.

And doesnt even cost much with hard drives now so cheap.