[dm-devel] A small question about Device Mapper

[Mike Snitzer]

On Sun, Aug 23 2015 at  3:29am -0400,
Ni, Xun <xun.ni at intel.com> wrote:

> Hi, all:
> 
> I use device mapper to config a thin-provision for a block device, with dmsetup, with the following command:
> 
> Dmsetup create pool -table "0 `blockdev -getsize /dev/sdd1` thin-pool /dev/sdd2 /dev/sdd1 128 0"
> Dmsetup message /dev/mapper/pool 0 "create_thin 0"
> Dmsetup create snap1 -tabe "0 `blockdev -getsize /dev/sdd3` thin /dev/mapper/pool 0 /dev/sdd3"
> 
> Everything works well, but when I reboot the system, the block device is gone, I need to create the pool again...
> 
> Anyone has idea on how to make this config persistent?  I need to boot the kernel , the dm pool device shows after the MD device found.

use lvm to create a thinp device that activates on bootup (see lvmthin
manpage).