[ale] lvconvert adding mirror speed considerations

[Phil Turmel]

You might have better results with pvmove.  Does basically what you've
described, but mirrors then removes stripe by stripe.  Not the whole LV.

On 12/01/2016 05:04 PM, Lightner, Jeffrey wrote:
> We’re in the process of migrating from one disk array to another.
> 
>  
> 
> The method we’re using is to zone in the new array to the same fabric(s)
> in which we have the existing servers and old array then allocate
> storage from the new array to the servers.  
> 
> We then use vgextend to add the new storage device PVs to the existing
> VG and also add a small device to be used for LVM mirror logging.  
> After that we use lvconvert to turn on mirroring for an LV specifying
> the new PVs (including the log device).
> Once the mirror is complete we do lvconvert to turn off mirroring
> specifying the old PVs to remove (and the log device).
> 
> This worked fine for a couple of smaller LVs we did yesterday.   We then
> started one to a 6.3 TB LV.   That has now been running for over 24
> hours and appears it will complete around 10 PM tonight.