El Vie 13 Dic 2002 09:06, Peter Stokes escribió:
> Hi Alan
>
> dd will only copy block for block normally, so if you are copying from a
> 40Gb disk to an 80Gb, the resulting filesystem will still only be 40Gb.
>
> Much better to use dump/restore etc and reinstall LILO etc to transfer it.

The use of dump/restore is heavily deprecated by Linus himself; have a look at 
the mail below.

Toshiro.


From: Linus Torvalds 
To: Neil Conway 
Subject: Re: [PATCH] SMP race in ext2 - metadata corruption. 
Date: Fri, 27 Apr 2001 09:59:46 -0700 (PDT) 
Cc: Kernel Mailing List linux-kernel At vger Dot kernel Dot org   

[ linux-kernel added back as a cc ] 

On Fri, 27 Apr 2001, Neil Conway wrote:     
>> I'm surprised that dump is deprecated (by you at least ;-)). What to 
>  use instead for backups on machines that can't umount disks regularly? 

Note that dump simply won't work reliably at all even in 2.4.x: the buffer 
cache and the page cache (where all the actual data is) are not coherent. 
This is only going to get even worse in 2.5.x, when the directories are moved 
into the page cache as well. 

So anybody who depends on "dump" getting backups right is already playing 
Russian roulette with their backups. It's not at all guaranteed to get the 
right results - you may end up having stale data in the buffer cache that 
ends up being "backed up".

Dump was a stupid program in the first place. Leave it behind.   

> I've always thought "tar" was a bit undesirable (updates atimes or  
> ctimes for example). 

Right now, the cpio/tar/xxx solutions are definitely the best ones, and will 
work on multiple filesystems (another limitation of "dump"). Whatever 
problems they have, they are still better than the _guaranteed_(*) data 
corruptions of "dump". 

However, it may be that in the long run it would be advantageous to have a 
"filesystem maintenance interface" for doing things like backups and 
defragmentation.. 

Linus 

(*) Dump may work fine for you a thousand times. But it _will_ fail under the 
right circumstances. And there is nothing you can do about

-- 
Toshiro

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