IBM AIX Continuous Availability Features - IBM Redbooks
IBM AIX Continuous Availability Features - IBM Redbooks
IBM AIX Continuous Availability Features - IBM Redbooks
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The virtualization introduced with the workload partition (WPAR) allows WPAR checkpoint<br />
and WPAR resume functionalities. The functionality of checkpoint and resume of a workload<br />
partition on another system is called live application mobility, as explained here:<br />
► Checkpoint consists of taking a real-time snapshot of the WPAR content and dumping it to<br />
disk. This file on disk is called a statefile. The snapshot will interrupt all processes to reach<br />
a quiescence point to allow the scan and capture of all resources in memory into the<br />
statefile.<br />
► Resume consists of recreating a WPAR and reloading its content in memory on another<br />
system from the previous statefile, and then resuming its processing. From the user<br />
perspective, it is as if the application just paused for a moment.<br />
Live application mobility requirements<br />
Note: Live application mobility is a completely separate technology from live partition<br />
mobility. However, they can coexist on a system that can match the prerequisites of both.<br />
For live partition mobility, each participating logical partition and machine must be configured<br />
the same way for the workload partition. This includes:<br />
► The same file systems needed by the application via NFS V3 or NFS V4.<br />
► Similar network functionalities (usually the same subnet, with routing implications).<br />
► Enough space to handle the data created during the relocation process. (Estimating the<br />
size is very difficult since it would include the virtual application size, some socket<br />
information, and possible file descriptor information.)<br />
► The same operating system level and technology maintenance level (TL).<br />
Note: In addition to operating system requirements, if not on shared file systems (NFS),<br />
then application binaries must be at the same level (identical).<br />
For more information about workload partitions and live application mobility, refer to the <strong>IBM</strong><br />
<strong>Redbooks</strong> publication Introduction to Workload Partition Management in <strong>IBM</strong> <strong>AIX</strong> Version 6,<br />
SG24-7431.<br />
Chapter 2. <strong>AIX</strong> continuous availability features 53
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