Pluggable Storage Architecture

[zeebahi]

Hi there,

I am trying to understand Pluggable Storage Architecture .

VMware Knowledge Base

Based on the above link:

What does NMP do?

• Manages physical path claiming and unclaiming.
• Registers and de-registers logical devices.

1) What does "physical path claiming and unclaiming " mean above?

2) What does "Registers and de-registers logical devices" mean above?  I believe logical devices means LUN here , if so, what does Register and degister do?

Thanks and have a good night!!

[NathanosBlightc · Accepted solution]

Ans to 1st Q: Based on VMware documentary: After rescanning the storage adapters, the host discovers all physical paths to the available storage devices for that ESXi particular host and based on claim rules ESXi determines which multipathing plug-in (MPP) should claim the paths to a particular device and become responsible for managing the multipathing support for the device. The ESXi host performs a periodic path evaluation every 5 minutes causing any unclaimed paths to be claimed by the appropriate MPP.

Ans to 2nd Q: After managing the physical path to the available storages, now it's time for register LUNs of each storage device to the ESXi Hosts or even de-register them.