I am building a 480GB RAID5 fileserver at home to store FLAC rips of my CDs (they won't last forever.) I want to additionally add a level of par redundancy to these data files to ensure that if they do get corrupted, I can fix them...

Most of the guides I've seen are related to UseNet as opposed to personal file archiving...could someone give me a few pointers? My concern is regarding the settings for the Block Allocation, Redundancy, Recovery File Size, etc.

This is for approximately 300GB of FLAC.

Regards,
Cerebus

You'll find some interesting information in this thread.

Basically:
The lower recovery block size, the better - and slower
1 set of par files for 1 album seems to be good.
If you have reliable software that can read at least parts of corrupted files, there sould be no difference between using one big or several small files.

Wow - that thread's a bit deep for me. I'm having trouble decoding what I'll need to do. I can understand having a set of par files for each album - but (using QuickPar, for example):

Is the source block count pre-calculated? How do you assign that value?

What does redundancy represent?

I guess I'm simply lost as far as how this works - it's very confusing to me. I'll read more FAQs, but I could use a bit more info, if anyone can help me out.

Regards

Hi.
I use the following config for the PAR2 archives on my backups in CD and DVD:

- Block size 2048; because its the minimun error size posible in a DATA-CD, I suposse that the best idea its to select a Block size coincident to the cluster size of your HDs... (its a supossal)

- One only file per folder; have a lot of separated files don't mean a higher protection level, its only usefull to tranfer PAR files over the net...

- 10% redundancy. This means that if about 10% of the data of my files get corrupted, I'll be able to recover it fully. 10% its an acceptable value for me, considering "random" errors on my data, serious medium damages (scratches)... and a acceptable waste of space by the PAR files :-)

You must evalute the "level of protection" you want to your files ;-)

I know it's not the exact situation you are planning, but I suposse maybe a orientation to you.

Best regards.
b:.

How do you get the block size so low for larger FLAC files? Those files are 25-35 MB on average and I can't QuickPar to accept that low of a 2048 multiple. So I've been using 102,400 block size, which is 2048x50=102400. Also, how do you choose just 1 file as the output? That setting is greyed out on my version of QuickPar (0.7.5) and I can't seem to find a setting.

what about using commandline version, with a line given by me at end of that long thread

http://www.hydrogenaudio.org/forums/index....hl=par2&st=100&

I guess I'm too stupid to figure out that command line. Should I assume this is the only way? Or is it OK to stick with 102,400 block size on large lossless files and continue to use windows QuickPar 0.7.5?

sweep par2 c -r15 -n1 -s70000 par2file *.*


s = 70000 as example, you can type in any value u want...

r=15 = 15% redundancy, u can type in other values, of course..

http://4nykey.nm.ru/tmp/par2-0.3.zip


User's report:

Par2ing a lot directories & subdirectories in 1 step:




par2cmdline-0.2.x86.win32.zip
worked well together with sweep.exe in DOSbox.

get it here:
http://parchive.sourceforge.net/
or directly here:
http://prdownloads.sourceforge.net/parchiv...32.zip?download

get sweep from case's page:
http://www.saunalahti.fi/cse/files/Sweep.zip


Install:

Ensuring sweep.exe and par2.exe (the commandline version mentioned above are in your path : /windows/system32/ dir (for NT, see equivilant for your OS)




Usage:

Every subdirectory was treated as single directory.

I tried eg. this commandline:

sweep par2 c -r15 -n1 -s384000 par2file *.*





some remarks:

smaller blocksize than -s 380 kiloByte is better, but longer time.

r15 : 15% redundancy, variable
n = 1 : 1 par2 file, you can leave n option away
You could adjust r, n, s to your needs.
n does not affect the recovery quality,
r , s influence the recovery quality/computing time.


par2 c -r15 -n1 -s384000 par2file *.*



time = const. * r% * 1/s

Time is proportional to : redundancy * smaller_blocksize






Out of readme:

Naming, wildcards:



If test.mpg had been split into multiple RAR files, then you could use:

par2 create test.mpg.rar.par2 test.mpg.part*.rar

The files filename "test.mpg.rar.par2" says what you want the par2 files to
be called and "test.mpg.part*.rar" should select all of the RAR files.








Addition:


Summary of commandlines:


Create par2:

sweep par2 c -r15 -n1 -s384000 par2file *.*


instead of s=384000, you can try smaller values, but the computing time will increase proportional , eg : 192000 ==>> twice the time than for s=384000.
same for R=15, amount of recovery data in %. eg. half amount in % ==>> half time.



Check:

sweep par2 v *.par2


Repair:

par2 r(epair) [options] <par2 file> [files]

This post has been edited by user on Nov 13 2003, 10:47 AM

BTW is there a command line compile for PAR2 0.3 for Win32? Couldn't find anywhere.

User - don't take this the wrong way, but your post is very difficult to comprehend. If it's that difficult to change a setting in QuickPar, then I choose not to worry about it. I'm not even going to attempt to mess around with command prompts just to lower block size. Thanks anyway for the post. I tried to make sense of it and could not. I'm sure many others will find it usefull. Cheers!

Daffy

Hi atici, there is a compile for 0.3, long time given in my posts....


*snip*

sweep par2 c -r15 -n1 -s70000 par2file *.*


s = 70000 as example, you can type in any value u want...

r=15 = 15% redundancy, u can type in other values, of course..

http://4nykey.nm.ru/tmp/par2-0.3.zip


*snip*






@ Daffy:

err, DOS-box you start simply in your windows tools, which you have automatically installed in your windows.

Then it is only a copy & paste of the given commandline.

s = blocksize, if you want something else than 70000 of my example,
r = amount of resulting recoevery data in % , eg. 15 = 15%, or take 5% or 10% or whatever makes sense for you.

The link above does not work for me .
Does anybody know some other?
10x

It does, it's tricky. Follow the link and there's another link there. Worked in IE but not in Opera.

Daffy, the "Number of Recovery Files" setting in QuickPar is related to the "Recovery File Size" setting.

If you choose "Variable (limited to size of largest data file)" for "Recovery File Size", then QuickPar calculates the "Number of Recovery Files" and will not permit you to change it.

If you select either of the other two choices for "Recovery File Size", then you will be able to adjust the value of "Number of Recovery Files" (including setting it to 1).

Where can I download par2cmdline 0.3 windows compile?
This download par2-0.3.zip doesn't work anymore

Yeah, "save as" no-worky for some reason, open http://4nykey.nm.ru/tmp and leftclick does (in firebird at least).
Anyway, here is another copy.

Thank you very much for the downloads

*

at * you find the 0.3 compile and a short guide with pics.

MOD: * no links or names of ripping groups please.