## 2.5.5 Virtual Flash Memory 

IBM Virtual Flash Memory (VFM) FC 0614 replaces the Flash Express features (0402 and 0403) that were available on the IBM z13s. It offers up to 2.0 TB of virtual flash memory in up to four 512 MB increments for improved application availability and to handle paging workload spikes. 

No application changes are required to change from IBM Flash Express to VFM. Consider the following points: 

GLYPH<SM590000> Dialed memory + zVFM = total hardware plugged 

GLYPH<SM590000> Dialed memory + Plan Ahead memory + VFM = total hardware plugged 

VFM is offered as a dialed 512GB memory increment size. Feature code 0614 represents one 512GB zVFM increment, as shown in the following example: 

FC 0614 - Min=0, Max=4 

VFM is designed to help improve availability and handling of paging workload spikes when z/OS V2.1, V2.2, or V2.3, or on z/OS V1.13$^{7}$ is run. With this support, z/OS is designed to help improve system availability and responsiveness by using VFM across transitional workload events, such as market openings and diagnostic data collection. z/OS is also designed to help improve processor performance by supporting middleware use of pageable large (1 MB) pages. 

VFM can also be used in coupling facility images to provide extended capacity and availability for workloads that are use IBM WebSphere MQ Shared Queues structures. The use of VFM can help availability by reducing latency from paging delays that can occur at the start of the workday or during other transitional periods. It is also designed to help eliminate delays that can occur when collecting diagnostic data during failures. 

VFM can help organizations meet their most demanding service level agreements and compete more effectively. VFM is easy to configure, and provides rapid time to value. 

## 2.5.6 Preplanned memory 

Preplanned memory helps plan for nondisruptive memory upgrades. The required hardware is pre-plugged based on a target capacity that is specified by the customer. This pre-plugged hardware is enabled by way of an LICCC order that is placed by the customer when they determine that more memory capacity is needed. The pre-plugged memory can be made available through a LICCC update. 

For more information about ordering this LICCC, see the following resources: 

GLYPH<SM590000> The IBM Resource Link website (login required) 

GLYPH<SM590000> Your IBM representative 

