Hello,

Need to an upgrade at the customer from 3.1 to 4.0sp1.

Just need some clarification on this part of the upgrade:

Config# upgrade check
Please enter the pathname of the local upgrader image: C:\Program Files\EMC\Centera\4_0\GlobalServices\lib\upgrader-build-4.0-112.tgz
Please enter the CentraStar upgrade version: 4.0.1-2958-968-20593

Available service levels for upgrade to the chosen version:
Name Description
-----------------------------------------------------------------------
RW Non disruptive upgrade with Read and Write Access
WO Non disruptive upgrade with Write Access Only
U Disruptive upgrade
-----------------------------------------------------------------------
Upgrade with which service level? (RW, WO, U): U [customer agreed upon service level]

Gathering input for Veto Checks
-----------------------------------
How many nodes do you expect in the cluster?: 8


I need to know about these upgrade terms. What is the U upgrade path?