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Topic: Parchive (Read 31894 times) previous topic - next topic
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Parchive

Hi, I wanted to know if there is a par generation tool that you can input a root directory to & will create PAR recovery volumes for each subdirectory contained.

Parchive

Reply #1 –
How about searching for all files inside the root direcory and then dropping all found items in QuickPar?

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Reply #2 –
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How about searching for all files inside the root direcory and then dropping all found items in QuickPar?
[a href="index.php?act=findpost&pid=269889"][{POST_SNAPBACK}][/a]

The problem with that is that the par files are created in the root directory, I want each sub folder to have it's own par files.

I work with like 50 folders, & 12 files in each folder each time I back-up so it's inconvenient to have to go folder by folder with QuickPar.

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Reply #3 –
Could you do this with Sweep?  You feed it a command line and it executes it recursively on the directory tree.

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Reply #4 –
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The problem with that is that the par files are created in the root directory, I want each sub folder to have it's own par files.

I work with like 50 folders, & 12 files in each folder each time I back-up so it's inconvenient to have to go folder by folder with QuickPar.
[a href="index.php?act=findpost&pid=269900"][{POST_SNAPBACK}][/a]

That's true. However, creating a single par for all files results in higher efficiency.

Parchive

Reply #6 –
Yes, use sweep with par2cmdline.

I use that method with my music backups...

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Reply #7 –
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Yes, use sweep with par2cmdline.

I use that method with my music backups...
[a href="index.php?act=findpost&pid=269919"][{POST_SNAPBACK}][/a]

Could anyone suggest which parameters to use with par2cmdline?

& yes this is a muisc back-up to DVD-R, each folder is an album & the files are in mpc format (about 5MB per file) but I also have extraction logs, encoding logs, & CUE sheets (about 2KB per file) for each album.

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Reply #8 –
sweep par2 c -r<redundancy percentage> -s<block size> *

I think this is kinda self-explanatory... This will create par2 files of all files in the directory. If you want more options to configure recovery file sizes and such, check the usage of par2.exe

This has some strange naming effects. For example, with a directory containing:

Air - Talkie Walkie.cue
Air - Talkie Walkie.log
Air - Talkie Walkie.wv

the command line generates files called "Air - Talkie Walkie.cue.par2" etc. So it most likely bases the file name off the first file in the directory list.

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Reply #9 –
Wouldnt you be better off making an ISO of your completed disc and making PAR files of that? If the Disc becomes damaged, you can just rip the entire thing using ISO Buster and fix the broken parts, in theory...

Parchive

Reply #10 –
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Wouldnt you be better off making an ISO of your completed disc and making PAR files of that? If the Disc becomes damaged, you can just rip the entire thing using ISO Buster and fix the broken parts, in theory...
[a href="index.php?act=findpost&pid=269952"][{POST_SNAPBACK}][/a]

That's a pretty good idea, I'll give that a try.

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Reply #11 –
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par generation tool that you can input a root directory to & will create PAR recovery volumes

I'm wrestling with the same issue . I'd like to have 1 set of PARs for the entire DVD (redundancy a lot more effective). I want the PARs to be based on files, not ISO, because the ISO might not extract: see this thread (also read tgh's post on the 2nd page).
However I still want the option of using ISO (as a last alternative). Quickpar allows this: it finds PARs within an ISO (although only one set).

However since Quickpar doesn't have directory support yet, these wishes don't go together, unless I avoid directories and store all files in the root...

Westgroveg, in your situation I'd store each album folder in a ZIP file (without compression), store the ZIPs in the DVD root, together with a PAR set based on all these  ZIPs. Make sure you create more PAR data than a typical ZIP file size (preferably a multiple).
To me this method is not an option because my (lossless album) folders are too large to be safe.

EDIT: rewrote post, it was not clear enough

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Reply #13 –
Quote
Quote
par generation tool that you can input a root directory to & will create PAR recovery volumes

I'm wrestling with the same issue . I'd like to have one set of PARs for the entire DVD (redundancy a lot more effective) while keeping the possibility of repair from within a damaged ISO of the DVD.
However since Quickpar doesn't have directory support yet, these 2 don't go together, unless I avoid directories and store all files in the root...

BTW, it's good to know that in case the 'TOC' is damaged, PAR repair is still possible, but Quickpar will only use 1 set of PARs (so you're screwed if you have a set in each album folder).
[a href="index.php?act=findpost&pid=269955"][{POST_SNAPBACK}][/a]


I think Ollie’s idea is a good one, recovery would probably work a lot faster if the corrupt source file is on hard disk.

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Reply #14 –
After reading the thread (see link in my previous post) I no longer dare to rely on ISO only. Maybe my concern is unjustified (I hope so) but I don't bet on a horse that might be handicapped.

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Reply #15 –
That thread seems to conclude that you can’t extract corrupt files from a DVD which is wrong. Also most of it has to do with corrupt PAR files.

I would extract with DVD decrypter in ISO mode, set hardware read retries to 1 & tick ignore errors. This would allow me to extract the corrupt ISO file, then I would grab my PAR files (which I would store on CD-R), copy them to the same folder as the corrupt ISO file & begin recovery.

Zipping each folder is out of the question, it’s too inconvenient

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Reply #16 –
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That thread seems to conclude that you can’t extract corrupt files from a DVD which is wrong.
I would extract with DVD decrypter in ISO mode, set hardware read retries to 1 & tick ignore errors.

It says that extraction is impossible in case an entire sector is unreadable. Has anyone experience with extracting an ISO from a damaged DVD or CD?

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Reply #17 –
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Quote
That thread seems to conclude that you can’t extract corrupt files from a DVD which is wrong.
I would extract with DVD decrypter in ISO mode, set hardware read retries to 1 & tick ignore errors.

It says that extraction is impossible in case an entire sector is unreadable. Has anyone experience with extracting an ISO from a damaged DVD or CD?
[a href="index.php?act=findpost&pid=269967"][{POST_SNAPBACK}][/a]

This is not the case with DVD decrypter.

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Reply #18 –
The sweep par2 method with parameter examples is described at www.high-quality.ch.vu - users's Audio High Quality Tutorials & Guides


Though I changed my method some time ago to create ca. 10% recovery data from all files of the entire DVD, 4.5 GB,
reason is the higher probability to restore corrupt files on the DVD.

I started writing a security article/rewrite of the par2 chapter for high-quality.ch.vu pages:
1st draw:


Security strategies against data failures, dead HDs, corrupted files on DVD.



Heat is main factor, which lets HD die.

My strategy, to avoid temperatures over 30°C, like 40°C, which are way to high:

I have big tower, and have 1 slot over and 1 slot below the HD free.
This allows natural air flow and cooling, enough for silent mode

If HD is stressed by replaygaining a lot of albums, or moving around a lot of data,
I switch on manually a fan blowing air from outside over the HD.


Recovery par2 data on HD or DVD media:


I changed my par2 way described at http://www.high-quality.ch.vu a little bit:

Now I create par2 data for all files on 1 DVD !
I copy all files to 1 direcotry, or add them in Quickpar gui,
so I have 4.5 GB data.
practical setting for slow pc, like P3-800 MHz:

block size ca. 1.5 MB,
results to ca. 3300 source blocks (of the 4.35 GB data)
redundancy, recovery data files: 10%, ca. 450 MB for each DVD,
split par2 files to 10 eg.
this will result to a computing time of 4-5 hours for P3-800.

This new way offers clearly higher probability to restore files on a damaged DVD.



Music backup strategy:

backup of the album !

1. Lossless album rip, stored on DVD 1.
2. MPC (1.14, 1.15t) --quality (7 --ms 15, 7.5 --ms 15 or best 8 --ms 15) --xlevel same album, on DVD 2.

probability, that both DVDs have errors at same music files ?
low.

MPC at those high qualities offers a nearly transparent backup, at least without annoying artefacts, even with possibility to transcode eg. to good mp3, with warranty to not get annoying or  listenable transcoding artefacts, at least for casual listening, ABXing may be different.
And this at very low costs regarding media or space.






btw., any medium will die sooner or later, but big HDs sooner..
magnetical devices suffer from heat and a lot of usage.

DVDs with music are not in use so often, only when u really need it, opposite to big HD with all-in-one usage.

optical devices don't last till eternity, too, but there are cheap new developments over years, see:

CD 0.7 GB
DVD 4.35 GB
.
DVD+DL 8.5 GB
.
.
Blue-Ray ca. 30 GB ?

So, after some time re-copying will be cheap and make the data safer.
 

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Reply #19 –
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I would extract with DVD decrypter in ISO mode, set hardware read retries to 1 & tick ignore errors. This would allow me to extract the corrupt ISO file, then I would grab my PAR files (which I would store on CD-R), copy them to the same folder as the corrupt ISO file & begin recovery.
[a href="index.php?act=findpost&pid=269966"][{POST_SNAPBACK}][/a]

I believe this won't work since AFAIK DVDDecrypter skips bad sectors whereas we need to be replaced with dummy data instead.

I personally transfer all my files in a single drivecrypt(http://www.securstar.com/) volume and then create a single par for this. In case of damage, i copy the drivecrypt volume to my hard disk with a special program i've written that replaces bad sectors with zeros and then do the repair. I think this method provides the higher redudancy of all. More over it overcomes the fact that QuickPar does not support directories. Finally i can backup this way my files without worrying about limitations in filename lengths of cd filesystems and the lack of unicode support of cd burning software. The only drawback of this method is drivecrypt not being free.

p.s. If drivecrypt volume is damaged it can be still mounted.

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Reply #20 –
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I personally transfer all my files in a single drivecrypt(http://www.securstar.com/) volume and then create a single par for this.


I think that encrypting my back-up's is a little overkill & it would also be a little inconvenient for my purposes.

Quote
In case of damage, i copy the drivecrypt volume to my hard disk with a special program i've written that replaces bad sectors with zeros and then do the repair.


It's a shame DVD Decreptor can't do this 

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Reply #21 –
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The only drawback of this method is drivecrypt not being free.

There is an open source disk encryption program: TrueCrypt.
http://truecrypt.sourceforge.net/
Isn't this good for you?

When you create the virtual drive, do you use encryption or compression, or the files are uncompressed and not encypted?

Quote
p.s. If drivecrypt volume is damaged it can be still mounted.
[a href="index.php?act=findpost&pid=270267"][{POST_SNAPBACK}][/a]

Yes, I feel this a key point! For ISO, is the same true? If we can extract a corrupted ISO, can it be mounted by Daemon Tools always, and can we see the file system (folders)?

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Reply #22 –
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I believe this won't work since AFAIK DVDDecrypter skips bad sectors whereas we need to be replaced with dummy data instead.

I thought so too. But Peter Clements (the Quickpar author) contradicted that (cfr. again the link I gave earlier). This is actually good news and I think will go with the method of ISO + PARs based on the ISO.

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Reply #23 –
Quote
Quote
I believe this won't work since AFAIK DVDDecrypter skips bad sectors whereas we need to be replaced with dummy data instead.

I thought so too. But Peter Clements (the Quickpar author) contradicted that (cfr. again the link I gave earlier). This is actually good news and I think will go with the method of ISO + PARs based on the ISO.
[a href="index.php?act=findpost&pid=270434"][{POST_SNAPBACK}][/a]

@geopoul

I am just starting to learn about computer hardware so have very little knowledge about how data communication in a computer works but do you think that if the corrupt bits are removed from the file instead of replaced with null data the file becomes shorter & when recovery is attempted it will think starting at the first error everything in the file is corrupt?

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Reply #24 –
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I am just starting to learn about computer hardware so have very little knowledge about how data communication in a computer works but do you think that if the corrupt bits are removed from the file instead of replaced with null data the file becomes shorter & when recovery is attempted it will think starting at the first error everything in the file is corrupt?
[a href="index.php?act=findpost&pid=270446"][{POST_SNAPBACK}][/a]


That's correct.

As for DVDDecrypter there is still the problem that it supports only dvd video discs, isn't it?

edit: read my next post