[linux-lvm] Solving the "metadata too large for circular buffer" condition

Andrew Gideon ag2827189 at tagmall.com
Wed Nov 24 21:35:38 UTC 2010

On Wed, 24 Nov 2010 20:28:11 +0000, Andrew Gideon wrote:

> But even if two segments are moved from dislocated locations to
> immediately adjacent locations, I see nothing which says that these two
> segments would be combined into a single segment.  So I'm not clear how
> fragmentation can be reduced.

This one part I was able to answer myself with some experimentation.  
pvmove is actually smart enough that, if two segments that are logically 
contiguous are placed such that they're physically contiguous, they are 
aggregated into a single segment.

Unfortunately, I cannot use pvmove in my production environment since it 
needs to create a temporary volume for a move and this runs into the 
"metadata too large" error.

So I'm still looking at how to solve this problem either with new PVs 
(and removing the metadata from the previous PVs, if I've understood this 
correctly) and/or moving the metadata to an external file.

	- Andrew

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