[Cialug] Moving Linux from one disk to another

Josh More morej at alliancetechnologies.net
Thu Sep 4 16:48:04 CDT 2008


I generally agree, but want to mention that ReiserFS only sorta supports
live resizing.  I don't recommend relying on that feature in a
production environment.

We've had issues.  

The solution involved backup tapes.

That is all.  :)



-Josh More, RHCE, CISSP, NCLP, GIAC 
 morej at alliancetechnologies.net 
 515-245-7701

>>> Zachary Kotlarek <zach at kotlarek.com> 09/04/08 4:41 PM >>>

On Sep 4, 2008, at 4:14 PM, Paul Gray wrote:

> dd takes too long

That depends on your usage. dd can be significantly faster if you have  
a mostly full disk, or a large number of small file, or both. But a  
file-based copy like tar or rsync will be much faster if you have a  
mostly empty disk.

In any case, if you're going to copy files (with tar, cp, rsync, etc.)  
as opposed to blocked (with dd) and are booted off another disk be  
sure to use numeric UID/GIDs or you're likely to end up with bad  
ownership.

> and isn't too kind to resizing partitions

Unless the partition layout on the disk prevents contiguous expansion  
it shouldn't be a problem. After the copy just rewrite the partition  
map and grow the FS.

But I agree with the LVM sentiment -- it makes things like partitions  
and physical disk layout almost inconsequential. If the system were  
setup with LVM in the first place you could add the second drive,  
migrate the data, and remove the old drive without even rebooting.  
Combine that with a file system that supports live resizing (JFS, XFS,  
ResierFS, ext* with appropriate kernel support, etc.) and you wouldn't  
even need to unmount anything to use the extra space.

	Zach




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