Re: Huge archive and last slice

Denis Corbin <[email protected]> Tue, 12 Dec 2023 20:48:05 +0100

Newsgroups	gmane.comp.sysutils.backup.dar.support
Message-ID	<[email protected]>

Thank you John for your pertinent remarks and continuous support ;)

On 12/12/2023 20:22, John Goerzen wrote:
> On Tue, Dec 12 2023, Denis Corbin wrote:
> 
>>
>>> I was wondering if it is possible to "extract" from the last slice only the
>>> relevant information needed for the recovery. I can understand that is it
>>> convenient to keep them in the last slice because usually it is the smallest
>>> one, but in case of huge archives its size can be relevant.
>>
>> Yes, the is precisely the isolated catalog.
> 
> To amplify this point a bit:
> 
> Every dar archive contains a "catalog", which is added at the end of the
> last slice, and is the directory information (including slice number) of
> every file within the archive and other assorted metadata.
> 
> You can also have an "isolated catalog", in which only the catalog
> portion is saved to a separate file.  This is exactly what you want.
> 
> There are two common ways to create this catalog:
> 
> 1) At the same time you create the archive itself, with the
> --on-fly-isolate option
> 
> 2) From an existing archive, using the --isolate option.
> 
> One use for this is to make incremental backups without needing to have
> the previous backup available.  You can simply reference its isolated
> catalog, and then dar will figure out what to do.
> 
> I have some examples of this on my blog here:
> 
> https://changelog.complete.org/archives/10527-using-dar-for-data-archiving
> 
> (ignore the bits about dar_manager as they are irrelevant to what you're
> asking)
> 
> - John
> 
> 
> 
>>
>>> PS: I must thanks John Goerzen for his support in setting up dar w/threads
>>> during my tests.
>>> Bests,
>>> R

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