Re: [dm-crypt] cryptsetup

[Gilles PIETRI <contact+dev@gilouweb.com>]

On 02/09/2009 03:14, solarflow99 wrote:
> can anyone say if this command is needed when resizing a partition?  
> What if I just used resize2fs? how could it know about the change of 
> size?  Also its a shame information like this has to be a secret, no one 
> seems to know or say anything about it.
> 
> Thanks,
> 

I have a question myself that is somehow related.. I do not know much 
about the internals of the payload alignment (--align-payload option of 
luksFormat), but I thought about something.. Say I have a RAID device of 
6 disks, that I have a stripe size of 64K, and that I use 
--align-payload (stripe width is 512 blocks here). Fine, should be 
aligned with the stripes.

Now, say that I add a disk there and migrate the array over it, the 
stripe width will increase to 640 blocks.. but how can I tell luks about 
it? Should I? Maybe newly written data could benefit from being aligned 
to the new stripe width (and let us say it won't be optimal for older 
data, but so be it)?

I know that xfs can then deal with the swidth growth by specifying the 
info in the mount options, so once cryptsetup knows about the geometry 
change, it should be fine..

Cheers,

Gilou