[SOLVED] WinRAR and Recovery Records

[Wolfinch]

1. Am I need to make recovery record for non-solid archive? What happen if there's a bad sector in future? I still can open the archive OR all corrupted?

2. If I have nested encrypted rar (Ex: Rar1 > Rar2) and want to make recovery record. I need to make it in every archive ("Rar1 + recovery" > "Rar2 + recovery")
OR
only the outer one ("Rar 1 + recovery" > Rar2)?

3. How much minimum recovery record needed to repair successfully?

 

[dwd999]

1. Am I need to make recovery record for non-solid archive? What happen if there's a bad sector in future? I still can open the archive OR all corrupted?

2. If I have nested encrypted rar (Ex: Rar1 > Rar2) and want to make recovery record. I need to make it in every archive ("Rar1 + recovery" > "Rar2 + recovery")
OR
only the outer one ("Rar 1 + recovery" > Rar2)?

3. How much minimum recovery record needed to repair successfully?

Most people use the QuickPar software for this purpose:

QuickPar for Windows

QuickPar is a PAR 2.0 recovery volume creation tool. Use it to protect and repair any data file.

www.quickpar.org.uk

 

[Ralston18]

@Wolffinch

You questions appear to be very much a homework assignment.

I also noted the same question being posted on another website.

https://linustechtips.com/topic/1423781-winrar-and-recovery-record/

= = = =

Forum rules prohibit answering homework questions.

In all fairness your questions may not be homework: however, overall there is no way on this end to know the truth of the matter.

So what you must do is to provide what you think are the answers to your questions, show your work and reasoning so to speak. Cite references. Provide links.

Post your answers accordingly and ask for comment and feedback.

 

[Wolfinch]

Most people use the QuickPar software for this purpose:

QuickPar for Windows

QuickPar is a PAR 2.0 recovery volume creation tool. Use it to protect and repair any data file.

www.quickpar.org.uk

Thanks, I'll look into it. And still, if I have nested rars, i need to make PAR for only the outer rar OR all rar inside rar too?

@Wolffinch

You questions appear to be very much a homework assignment.

I also noted the same question being posted on another website.

https://linustechtips.com/topic/1423781-winrar-and-recovery-record/

= = = =

Forum rules prohibit answering homework questions.

In all fairness your questions may not be homework: however, overall there is no way on this end to know the truth of the matter.

So what you must do is to provide what you think are the answers to your questions, show your work and reasoning so to speak. Cite references. Provide links.

Post your answers accordingly and ask for comment and feedback.

What is this homework thing? Literally homework? Well I dont know if there's a school or university give "homework" like this. But I dont know.

Why I ask in many forums? To prevent answer like this. If I dont get answer from one forum, I still can get it from another.

You want me to answer my own question? It's silly but okay. i'll do it

1. I dont think non-solid archive need recogery record as solid one. Because it doesnt have single stream encryption. So If one block become bad, we still can extract the other data, because its not single solid files. But of course adding recovery record is good option.

2. I think we can only add the outer RAR only. Because if the outer rar repaired, the inside rar can be repaired automatically. But I dont know, thats why I ask.

3. Maybe 5%? Dont know, thats why I ask

Provide links? How I can do that? If I found information about this out there, I dont need to ask here. Of course I dont have it.

So, what do you think about my answer? Is that assumption true?

Well, I still confused how this technical "paranoid" question == homework assigment.

 

[dwd999]

Thanks, I'll look into it. And still, if I have nested rars, i need to make PAR for only the outer rar OR all rar inside rar too?

If you're 100 percent certain the the nested rars are undamaged then you could just have pars for the outer rars. Just use the default quickpar settings and you should be OK.

 

[Ralston18]

It does happen that people post "homework", "assignment", or "project" questions in this forum (and other forums) hoping to get someone else to do the work.

As I stated: there is no way to really know the truth of the matter.

Sometimes, the answers are readily found and other times perhaps not. Learning to research and look for the less than obvious is a necessary life skill.

As for WinRAR some additional reading would likely prove helpful. Here is a link to help.

[Note: To include a link in future posts, click the "two link chain" icon in the middle of the tool bar above.]

https://documentation.help/WinRAR/

Note: Read the section on Recovery Volumes.....

And I found a number of other links by including "RAR", "nested", and "recovery", in my search criteria.

A couple of those sites raised other concerns.

Will bow out accordingly.

 

[Wolfinch]

I mailed WinRAR and got the asnwer (They dont ask if it's homework question or not.. lol)

And of course, MultiPar or QuickPar can be use as great solution too.

>1. I need recovery record for non-solid archive?
Yes, if you want to improve the chances of any RAR archives being successfully repaired after data damage, use the recovery record, you can also use recovery volumes but only for multivolume archives.
When damage resistance is the top priority, it is best to avoid solid archiving mode, even though non-solid archiving can result
in a lower compression ratio.

>1.1. If there's a bad sector in future? I still can open the archive OR ARE all corrupted?
Any files after a corrupted file may be unavailable, so you would be best to provide the recovery record or recovery volumes for important files as they are the best way to attempt recovery from corruption, bad sectors, or email transmission errors.
Note that recovery volumes are available only for multivolume archives.

>2. Make recovery records for nested encrypted rar files?
Typically we can't damage only an inner archive without damaging an outer archive. Also fixing an outer archive should normally fix an inner archive.
So if an inner archive is not stored separately, we suggest you add the recovery record only to the outer archive.
Note that archives with encrypted file names can only be repaired when a recovery record is present.

>3. How much minimum recovery record needed to repair successfully?
RAR recovery record allows to restore slightly less data than recovery record's own size.

[FONT=arial, helvetica, sans-serif]Note that repairing a damaged archive is not performed for archives with encrypted file names, as these can be repaired only if a recovery record is present. Recovery volumes can only be used with multivolume archives and a complete repair cannot always be guaranteed as each recovery volume can only reconstruct one missing volume file.

To protect an archive from damage, you need to specify the size of the recovery record in a percentage of the total archive size. As from WinRAR 6.10, the maximum allowed value is 1000%. Larger recovery records allow for recovery from more serious damage, but at the same time it increases the archive size, so 3 - 5% is usually optimal, but you could use 10% or even 20% for important backups.

Also the "Repair" command does not fix broken blocks in a recovery record. Only file data can be corrected. After successful archive repair, you may need to create a new recovery record for saved files.

While the recovery record improves the chances of repairing damaged archives, it does not guarantee a successful recovery.
So to improve the chances of any multivolume RAR archives being successfully repaired in case of data damage, use the recovery record and recovery volumes (where possible) when creating them and avoid solid archiving mode, even though non-solid archiving can result in a lower compression ratio.
The best way to ensure that bad sectors are avoided is to use regular external backups, and also save copies of important files on a different disk drive, or thumb drive.[/FONT]