Unix Server Consolidation Andrew Moss Midrange Design Engineering – Design and Integration amoss1@csc.com

Introduction This presentation provides an overview of some of the benefits that CSC and our clients would derive from server consolidation. The presentation describes the business benefits expected from server consolidation, and attempts to examine some common approaches and their benefits and limitations.

Types of Consolidation There are a number of approaches that can be taken to consolidate Unix/Linux services OS Instance consolidation Server consolidation on to large servers running multiple OS instances using hardware or software OS partitioning Consolidation using 3rd party virtualisation software – for example VMware for Linux Application Consolidation Reducing the number of applications Running compatible applications on a single server Use of resource management to create a degree of application isolation

Drivers for Consolidation It is important to understand what the drivers for consolidation are, and what business benefits we are trying to obtain. Some of the reasons for consolidation are listed below Reduce number of applications Remove old hardware/software versions Decrease software and hardware maintenance costs Reduce power and footprint requirements Reduce the number of OS instances to be managed Provide flexibility in provisioning resources Tidy up existing environments that may not have been well designed or implemented Increase understanding of environments that have grown over many years and may not be well understood Add functionality – for example ease of DR and Backup

OS Instance consolidation Consolidation of many OS instances onto a single server provides a number of advantages Much improved hardware utilisation Removal of outdated hardware Decreased hardware and software maintenance costs Reduced power and cooling requirements Upgrade of OS version Increased flexibility in provisioning Less hardware to recover during a DR situation

OS Instance consolidation OS instance consolidation alone however does not address many of our identified business drivers for consolidation, and actually adds cost and complexity in some areas Does nothing to reduce number of applications Does not reduce the number of OS instances to be managed May require newer OS versions that do not support current applications Does little to tidy up existing environments that may not have been well designed or implemented ( other than improved OS currency ) Does nothing to improve the number of applications that have to be recovered in a DR situation - creation of partitions / virtualisation layer may actually increase the time to recover vital services Virtualisation/partitioning technologies add cost, complexity and administrative overhead for the system administrator. There is also a performance overhead. Where larger servers are deployed there is a per CPU cost premium over smaller servers ( See backup slides ) Failure of a single server results in bigger impact to business, may be addressed by HA clustering but this adds system administration complexity Maintenance requires agreement from more business units

Consolidation – Decrease number of Applications Consolidation by decreasing the number of applications has the potential to bring a lot more advantages Reduced number of applications removes cost and complexity from the environment Removal of older applications removes dependencies – for example old application versions may not run on new OS/Hardware Simplification of the application environment removes clashes between applications and therefore allows a reduction in the number of OS instances to be managed Drive utilisation of servers by consolidating functionality on to a smaller number of servers Often allows improved business processes to be developed A reduction in the number of applications has a major impact on ease of DR, and ease of management

Consolidation – Decrease number of Applications Consolidation by decreasing the number of applications however is not initially a low cost option Can be very disruptive to client business during transition Requires input from client to define business processes May not be an option where historical data prevents removal of an application

Consolidate existing applications onto less OS instances Running multiple existing applications on a reduced number of OS instances provides a number of advantages No need for business changes to consolidate applications Drives server utilisation Reduces OS management overhead However it also brings a number of risks Possible incompatibilities between applications – different applications may require specific versions or modifications to the OS Applications may impact each others performance Security boundaries between applications are removed Failure of a single server results in bigger impact to business, may be addressed by HA clustering but this adds system administration complexity Maintenance requires agreement from more business units

Consolidate existing applications onto less OS instances – With resource management Introducing resource management addresses some of the issues Provides guaranteed levels of performance to individual applications Newer functionality such as Solaris Zones also provides a degree of fault isolation and name space ( security ) isolation. Resource management and Zones have some limitations Often requires newer OS versions – existing applications may not be certified or may not run at all on newer versions Can impact application functionality Increased system management effort required to configure Adds complexity, for example when fault finding Not available on some flavours of Unix and Linux May not be fully supported by infrastructure tools yet, for example backup products

Summary A combination of OS and application consolidation is required to gain all of the business benefits promised by consolidation. Many technologies will increase system management overhead and add cost and complexity in some areas – this increase in complexity has to be balanced against other benefits for example reduced maintenance, footprint, power, hardware costs and flexibility. Care is needed to target the most cost effective solution at the individual business problem – large partitioned or virtualised servers may not be the answer where workload is predictable and flexibility is not required. Consolidation of many services onto a single server also means that areas such as High Availability that were not a consideration before, may become important.

Backup Slides

Does it always make sense to virtualise ? One of the drivers to virtualise is to improve utilisation, However the table to the right shows that the cost of a CPU increases dramatically as you purchase larger servers ….. For example we have 4 workloads that vary between 4 and 8 CPU’s. The maximum CPU requirement is 32 CPUs. We could host this on a 24 way E6800 and assume that we will save 8 CPUs on average. However if we bought 4 8 way V880s they would cost $343,890 - Still a saving of $1/2 Million dollars on purchase price. Although this is an extreme example, similar situations will apply in the low end space – with solutions such as VMware we also need to allow for software license costs. Virtualisation often makes most sense where workload is unpredictable, or when workload does not map well to CPU boundaries CPU’s Sun List $ per CPU Relative 1 V120 $1,995 1.0 2 V240 $6,495 $3,247 1.6 4 V440 $15,995 $3,998 2.0 8 V880 $85,995 $10,749 5.4 24 E6800 $842,895 $35,120 17.6 36 E12K $1,389,330 $38,592 19.3 We Information extracted from CSC RDC overview Prices are indicative list prices taken from Sun web site Similar trends from other vendors (this is not Sun specific) Very simplified comparison based on acquisition price only No discounting applied Not a TCO comparison But serves to illustrate the point! Try this out with your own preferred vendor and discounting

Links to other useful information The following documents created by Midrange DE D&I may be useful Quick Overviews Unix Server Virtualisation Overview https://web02.sources.uk.csc.com/cscportal/providers/fileopen.asp?ID=10037964 Solaris Zones / Containers Overview https://web02.sources.uk.csc.com/cscportal/providers/fileopen.asp?ID=10037961 Detailed Presentations Unix Partitioning and Virtualisation technologies Presentation https://web02.sources.uk.csc.com/cscportal/providers/fileopen.asp?ID=10034953 Solaris Containers Overview and Configuration Guide https://web02.sources.uk.csc.com/cscportal/providers/fileopen.asp?ID=10035717 IBM Power 5 Overview https://web02.sources.uk.csc.com/cscportal/providers/fileopen.asp?ID=10034530 IBM Power 5 Virtual IO Server Configuration https://web02.sources.uk.csc.com/cscportal/providers/fileopen.asp?ID=10034531