content_image/1007058.jpg
Figure 2-3 on page 22 shows a cluster including a quorum site with limited capacity. 

<img src='content_image/1007058.jpg'>

The functions that can use quorum are noted in the following list: 

GLYPH<SM590000> Server-Time-Protocol (STP) can use a quorum (called Arbiter) to select the preferred time server 

GLYPH<SM590000> A clustered file system (GPFS or Spectrum Scale) uses quorum to maintain data consistency in the event of a node failure 

## 2.1.6 System partition configuration 

The traditional method of configuring logical partitions and I/O on IBM LinuxONE uses the I/O Definition File (IODF). In this book, we describe running the machine in IODF mode and configuring the machine using IODFs. 

Note:  More detail about I/O configuration on IBM LinuxONE can be found in 3.2, “Machine configuration on IBM LinuxONE” on page 55. 

## Dynamic Partition Manager 

A new partition management system, known as Dynamic Partition Manager (DPM), has been introduced on IBM LinuxONE. DPM provides a complete interface for defining IBM LinuxONE partitions, assigning resources to them, and starting and stopping them. DPM is designed to require less upfront knowledge of the I/O configuration concepts than when using IODFs. 

DPM supports most IBM LinuxONE hardware, including OSA Express and FICON Express adapters. 

At the time of this publication, DPM does not provide support for two important IBM LinuxONE functions that are important to the reference architecture described in this book. These functions are: 

GLYPH<SM590000> FICON channel-to-channel (CTC) devices 

GLYPH<SM590000> The LPAR to run a GDPS Virtual Appliance 

