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Database Virtual Server Candidacy Criteria

13 July,2011 by Tom Collins

Migrating database servers,  often requires decisions on whether to virtualize.  There are plenty of tests,  criteria and documentation on metrics for testing on virtualized database servers.

 I’m working on a large data centre migration. One of the objectives is to list out database servers  (DB2 and SQL Server)  which satisfy the criteria.

 Some quick formulas are useful. They do not substitute considerations for the performance stack, but act as a rule of thumb. 

These formulas are for Windows and Linux. A colleague uses these formula to create candidacy lists for large server farms.


Information required

Number of processors

Processor speed

Average Utilization % of Processor


No.Processors x Processor Speed x CPU Utilisation %  = CPU score

<= 4096  = Good Candidate

> 4096  =  Possible Candidate


Information required

Physical Memory

Memory utilise


Total Memory x Memory Utilisation %  = Memory Score

<=4096  =  Good Candidate

> 4096  and <=6144  = Likely Candidate

> 6144 = Possible Candidate

Disk IO

Information required

Daily Average Total IO rate (4K pages per second)


Daily Average Total IO rate(4k pages per second)   = Disk IO score

<=1000 IO per second  =  Good candidate

>1000 IO per second and  <= 3000 per second  = Likely candidate

> 3000 IO per second  = Possible Candidate

Related posts

Virtualization – and database servers

SQL Server – virtualization - is it a viable alternative

Author: Tom Collins (


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