[Novalug] LVM query

[James Ewing Cottrell 3rd]

On 7/19/2010 9:08 PM, Brander Snaxe wrote:
> What is the first track problem you mention? Is this something to do with LVM alignment? I have read about this before when dealing with filesystem alignment with RAID5 stripes. Also it comes into play with LVM. And it always comes into play with SSD drives apparently.
>
> [[[I assume that for plain LVM or for LVM+RAID (no striping) that the mis-alignment problem would be so negligible that worrying about is moot.]]]
>
> Just curious.
>
> Also, for anybody using LVM with XFS, forget about it unless you have a battery backed controller. LVM ignores barrier/nobarrier options on top of software RAID (at least it did when I last tried about 6 months ago).
>    
OOPS! I forgot to comment on part of your post, the part [[[I marked 
like this]]].

Yes, the alignment doesn't really matter in the LVM/RAID case, but if 
you ever try cloning your partitions via DD, assuming equal partitions 
sizes, you will be able to copy P1 to Pn, but not vice versa.

I don't normally do that except to back up my Windows partition. Crude, 
but effective.

JIM