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Methods to pause a z/VM guest: Optimize the resource utilization of idling servers
- Abstract
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This paper analyzes the behavior of Linux z/VM guests running a WebSphere workload or a relational database (RDB) workload when they are paused and restarted in an idle phase.
The absence of workload might not necessarily imply that a server is inactive from the Hypervisor perspective and its resource are free. The Linux suspend and resume function is compared to the z/VM CP STOP and BEGIN commands.
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Methods to pause a z/VM guest: Optimize the resource utilization of idling servers
- Creation date
- September 2011
Large Discontiguous Saved Segments (DCSS) Under Linux
- Abstract
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A Discontiguous Saved Segment (DCSS) is a z/VM technology used to share memory between z/VM guests. It is a powerful tool that gives z/VM administrators a way to provide high levels of resource sharing between guests, combined with excellent performance.
This paper focuses on three areas of application for a large DCSS: sharing code, sharing read-only data, and using a DCSS as a swap device.
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- Creation date
- April 2011
z/VM large memory
- Abstract
This report analyzes the results observed with Linux guests running a database server under online transaction processing (OLTP) workload in a z/VM environment using a relatively large amount of main memory (80 GB) and then also overcommitting that memory.
To test the z/VM memory management behavior, the memory was overcommitted up to a factor of two and the impact of the following z/VM memory management features were tested:
- VM Resource Manager Cooperative Memory Management (VMRMCMM), initially available with z/VM 5.2 (also known as CMM Version 1)
- Collaborative Memory Management Assist (CMMA), initially available with z/VM 5.3 (also known as CMM Version 2)
These features were expected to improve the overall system performance in cases where the overall z/VM system is constrained for real storage.
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- Creation date
- December 2007
z/VM and Xen virtualization performance
- Abstract
The paper analyzes the performance of the hypervisors z/VM on IBM System z and Xen on IBM System x when scaling the level of CPU and memory overcommitment. WebSphere Application Server 6.1 environments were scaled on an 8-way server, where each environment was a server triplet consisting of an IBM HTTP server, the application server and a database server. Each server resided on an individual Linux guest. Additionally the paper analyzes the impact of encryption.
The z/VM hypervisor shows significant advantages when scaling into CPU and memory overcommitment in throughput and response times.
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- Creation date
- January 2009
z/VM virtualization performance
- Abstract
The paper analyzes the performance of the z/VM virtualization features when scaling WebSphere Application Server 6.0.2 environments on an 8-way server.
Each environment is a server triplet consisting of an IBM HTTP server, a WebSphere application server and a DB2 UDB database server, where each server resides on an individual Linux guest. Up to 15 systems are defined running on virtual hardware provided by one System z. The work load and the number of server triplets were scaled, which leads finally to an environment having 2.5 times more virtual CPUs than physical CPUs.
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- Creation date
- September 2007
CMM
- Abstract
This presentation focuses on Cooperative Memory Management (CMM1) and Collaborative Memory Management (CMM2). They both regulate Linux memory requirements under z/VM. The presentation shows how to activate CMM1 and CMM2, and that both methods improve performance when z/VM hits a system memory constraint.
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- Creation date
- March 2009