higher agcount on LVM2 thinp volumes

[Chris Murphy]

On Aug 29, 2013, at 8:58 PM, Dave Chinner <david at fromorbit.com> wrote:
> 
> Check the contents of
> /sys/block/<dev>/queue/{minimum,optimal}_io_size for the single
> device, the standard LV and the thinp device.

physical device:

[root at f19s ~]# cat /sys/block/sda/queue/minimum_io_size 
512
[root at f19s ~]# cat /sys/block/sda/queue/optimal_io_size 
0

conventional LV on that physical device:
     
[root at f19s ~]# cat /sys/block/dm-0/queue/minimum_io_size 
512
[root at f19s ~]# cat /sys/block/dm-0/queue/optimal_io_size 
0


thinp pool and LV:

lrwxrwxrwx. 1 root root       7 Aug 29 20:46 vg1-thinp -> ../dm-3

[root at f19s ~]# cat /sys/block/dm-3/queue/minimum_io_size 
512
[root at f19s ~]# cat /sys/block/dm-3/queue/optimal_io_size 
262144
[root at f19s ~]# 

lrwxrwxrwx. 1 root root       7 Aug 29 20:47 vg1-data -> ../dm-4

[root at f19s ~]# cat /sys/block/dm-4/queue/minimum_io_size 
512
[root at f19s ~]# cat /sys/block/dm-4/queue/optimal_io_size 
262144


Chris Murphy