[dm-devel] Device Probing at boot time

[Shahsandeep Bhavana]

Hi,

  I want know how the device mapper knows about the various logical volume 
devices and their mapping tables at boot time.

Actually, I have implemented a new disk-allocation policy in LVM2 called 
snap-aware. Now, whenever I create a logical volume  using this allocation 
policy, it is visible and available for use until I reboot the machine. On 
reboot, LVM is able to read information about this logical volume from the 
metadata , but the device mapper loses all information about it including 
the path entries in /dev.

However, when I keep the allocation algorithm same and only change the 
name of the allocation policy to Contiguous, everything works fine.

So, I am wondering how can the name of an allocation policy effect the 
device mapper on reboot.

Bhavana