Virtual Clusters:Virtual Clusters:A Cost-Benefit Look Into the Future of Computing at CMUA Cost-Benefit Look Into the Future of Computing at CMU

Alok Chatterjee

Anusha Krishnakumar

November 25th 2002

Introduction - What is a Introduction - What is a Virtual Cluster?Virtual Cluster?

VC Locations– University Center VC (Apple grant)– GSIA (IBM ThinkPads)

“Laptop check-out system” very similar to library system

Background on “VC’s”– Planning process begun in 1994

GSIA Virtual ClusterGSIA Virtual Cluster

First VC opened in 1998 (pilot program)– 28 IBM ThinkPads

GSIA full service VC– 50 ThinkPads today

Various known problems going into VC project

GSIA VC CostsGSIA VC Costs

Main costs associated with VC:– Need for More Man-Power– Network issues (wireless supports far less bandwidth)

Further costs:– Laptop / Battery lifecycle

Replacement costs

– Skilled labor / Training costs– Waiting time

Back-to-back classes, etc

– Laptop availability Not available 24 hours

Need for More Man-PowerNeed for More Man-Power

• Training (i.e., logistics for running the cluster)

• Cluster needs to be constantly staffed

• Certain Technical Skills (e.g., technical support)

• Higher salaries associated with the above attributes

Network issuesNetwork issues

• Wireless supports far less bandwidth, resulting in more jams

• Users closer to wireless hubs tend to use up more bandwidth, detracting from other users’ usage capabilities

GSIA VC BenefitsGSIA VC Benefits

Various benefits too– Space conservation– Energy savings– Flexibility / Mobility

Space ConservationSpace Conservation

• Small checkout hub, located near classrooms / auditoriums

• The GSIA virtual cluster takes up approximately one-tenth of the space that the Baker cluster does

• Given the shortage of classrooms on campus, the potential benefits resulting from more virtual clusters, and, by extension, fewer desktop clusters, could be enormous

Energy SavingsEnergy Savings

– Laptops tend to take less energy than desktops

Dependent upon the power consumption of the battery charger

These computers will NOT be left on all the time like the cluster computers

Flexibility / MobilityFlexibility / Mobility

– All the benefits of a laptop, plus an Ethernet connection

– Especially useful given space constraints

– Can effectively control the size of the cluster

Wrap-upWrap-up

Various benefits and costs as mentioned earlier– Space, energy, replacement costs, etc

Success of Virtual Cluster system today– Laptops checked out on a regular basis, popular with

students and professors

Our recommendation– Expand the virtual cluster service and eliminate some

desktop clusters

Questions?Questions?