lvcreateopts ordering / sizing

[Thomas Neumann]

Hello Luke

On Friday 21 November 2014 14:24:27 Luke Alexander wrote:
> 1) be able to create an lv using extents from a specific physical device in
> the vg 
> 2) be able to allocate 100% of the extents from that specific device

What's the deeper meaning behind this? From just this description there's not 
much difference compared to using the physical volume directly. The only thing 
that I can think of is that you may want to grow the solr-lv with some extents 
from md2 later on. But if that's possible later then why don't you do it right 
from the start?

One other reason could be to make sure the disk I/O-queues for root and mnt 
are separate from solr - but to be frank I don't even know if LVM really works 
that way. It may as well be that the actual device I/O is indeed going into 
different queues, but shares the same queues (and latencies) on the LVM level. 

bye
thomas