Is the --sparse option suitable for .dbf files

[Dariusz Dolecki]

Please let me know

[Kevin Korb]

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Essentially, a sparse file is a file that is stored sparsely meaning
that any long string of nulls that happens to be on a filesystem block
will not actually be allocated by the filesystem so you don't have to
store that block of nothing. When you read such a file you get nulls
but they aren't actually read from disk. If you ever write something
to that part of the file the file size will not change but it will
occupy more disk space.

The only reason it doesn't work with grub is that grub is not using
the kernel to access the filesystem. It is using a very stripped down
filesystem module that is usually good enough to figure out which disk
sectors to load a kernel from but it can't handle sparseness. Pretty
much everything else won't know the difference.

Also, this is during a restore that I am talking about. I don't see a
problem with using --sparse on everything during the backup.

On 09/05/12 12:25, Dariusz Dolecki wrote:
> Please let me know
>
>

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Kevin Korb Phone: (407) 252-6853
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[Jason Haar]

On 06/09/12 04:31, Kevin Korb wrote:
> Also, this is during a restore that I am talking about. I don't see a
> problem with using --sparse on everything during the backup.

Conversely, is there any problem with NOT using sparse on sparse files?
i.e. I know it will use more space - but will a sparse file copied
somewhere by rsync NOT using the "--sparse" option be 100% equivalent to
the original?

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Jason Haar
Information Security Manager, Trimble Navigation Ltd.
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[Kevin Korb]

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Nope, it will just eat space storing nothings rather than generating
the nothings when you read the file.

Note that when you copy a sparse file sparsely it doesn't necessarily
sparse the same blocks so the files still might not be the same size.

On 09/05/12 20:26, Jason Haar wrote:
> On 06/09/12 04:31, Kevin Korb wrote:
>> Also, this is during a restore that I am talking about. I don't
>> see a problem with using --sparse on everything during the
>> backup.
>
> Conversely, is there any problem with NOT using sparse on sparse
> files? i.e. I know it will use more space - but will a sparse file
> copied somewhere by rsync NOT using the "--sparse" option be 100%
> equivalent to the original?
>

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Kevin Korb Phone: (407) 252-6853
Systems Administrator Internet:
FutureQuest, Inc. Ke...@FutureQuest.net (work)
Orlando, Florida k...@sanitarium.net (personal)
Web page: http://www.sanitarium.net/
PGP public key available on web site.
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