A difficult filesystem

Andy Armstrong andy at hexten.net
Thu Jun 21 00:54:33 BST 2007

On 20 Jun 2007, at 23:14, Eric Wilhelm wrote:
>> Any of the normal hard-link-preserving copying methods run out of
>> memory pretty early - for obvious reasons.
> I assume that includes rsync?

Yup, that was my first attempt. I may not have tried a very recent  
version though.

> If you're transferring the whole partition, any chance of getting  
> lvm to
> adopt the filesystem and migrate it across pv's?  (That's iffy, so try
> it on a disposable setup first.)
> Maybe more feasible would be to create a mirror with mdadm and then  
> just
> unplug the original once /proc/mdstat gives you the all-clear.

That's an interesting idea, thanks.

>> So I copied the whole filesystem (dd if=x of=y) onto the new device
> Is that `dd if=/dev/sda1 of=/dev/sdb1`? (pointing at the device or
> partition?)  Can you use an lv as a dd target (thus allowing  
> lvextend)?

Partition to partition.

>> While I'm waiting does anyone have tips for other tools that might be
>>   useful?
> Assuming you're talking about a dirvish-like setup, it might be  
> fastest
> to simply reconstruct the process that originally created the trees
> (but applying it to the repository->repository transfer rather than  
> the
> typical nightly host->repository usage.)

They're incremental backups of another box - and I'd like to keep the  
previous versions of files if possible. None of it is vital -  
anything really important lives in a few other places too - but I'd  
like to preserve it if possible.

> If it works, send me your code :-D

OK :)

Andy Armstrong, hexten.net

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