The system configuration must have sufficient dormant resources on the remaining drawers  in the system for the  evacuation  of the drawer that is to be replaced or upgraded. Dormant  resources include the following possibilities: The I/O connectivity must also support drawer removal. Most of the paths to the I/O feature  redundant I/O interconnect support in the I/O infrastructure (drawers) that enable connections  through multiple fanout cards. If sufficient resources are not present on the remaining drawers, certain non-critical LPARs  might need to be deactivated. One or more CPs, specialty engines, or storage might need to  be configured offline to reach the required level of available resources. Plan to address these  possibilities to help reduce operational errors. Include the planning as part of the initial installation and any follow-on upgrade that modifies  the operating environment. A client can use the Resource Link machine information report to  determine the number of drawers, active PUs, memory configuration, and channel layout.  If the z14 server is installed, click  Prepare for Enhanced Drawer Availability  in the Perform  Model Conversion window of the EDA process on the Hardware Management Console  (HMC). This task helps you determine the resources that are required to support the removal  of a drawer with acceptable degradation to the operating system images.  The EDA process determines which resources, including memory, PUs, and I/O paths, are  free to allow for the removal of a drawer. You can run this preparation on each drawer to  determine which resource changes are necessary. Use the results as input in the planning  stage to help identify critical resources.  With this planning information, you can examine the LPAR configuration and workload  priorities to determine how resources might be reduced and still allow the drawer to be  concurrently removed.  Include the following tasks in the planning process: Chapter 9. Reliability, availability, and serviceability  377 Exception:  Single-drawer systems cannot use the EDA procedure.  GLYPH<SM590000> Unused PUs or memory that is not enabled by LICCC GLYPH<SM590000> Inactive resources that are enabled by LICCC (memory that is not being used by any  activated LPARs) GLYPH<SM590000> Memory that is purchased with the flexible memory option GLYPH<SM590000> Extra drawers GLYPH<SM590000> Review of the z14 configuration to determine the following values: – Number of drawers that are installed and the number of PUs enabled. Consider the  following points: GLYPH<129> Use the Resource Link machine information or the HMC to determine the model,  number, and types of PUs (CPs, IFLs, ICFs, and zIIPs).  GLYPH<129> Determine the amount of memory (physically installed and LICCC-enabled). GLYPH<129> Work with your IBM Service Support Representative (IBM SSR) to determine the  memory card size in each drawer. The memory card sizes and the number of cards  that are installed for each drawer can be viewed from the SE under the CPC  configuration task list. Use the View Hardware Configuration option. 