[linux-lvm] 2 Q's: power outages during pvmove and fragmentation

[Joe Thornber]

On Sun, Jul 27, 2003 at 03:24:49PM +0200, Frank Van Damme wrote:
> 1: suppose my hamster bites my power cord during a pvmove and only half of the 
> data will have moved. How great a disaster does this result in? Does lvm move 
> one extend and does it write to disk which LE has been mapped to which PE, or 
> does it first write all the data and rewrite the metadata?

First off I encourage you to use LVM2 rather than LVM1.  An
interrupted pvmove can be resumed or aborted after a crash.

> 2: does lvm ever get fragmented if one moves data around across different 
> disks a lot?

The extent size is normally so large (4M+) that fragmentation isn't
really a big problem with LVM.  But we will be making a more general
remapping tool in the future that allows you to do this sort of thing.

- Joe