Control Your Network

Control on network in performance testing/Engineering
In performance testing most of the time we don't spend too much time on network and network related indicators but this plays a major role.
Here I'll capture few of the basic points which we should consider.
Case : Suppose we have servers having multiple LANS, to explain it further suppose in your lab there are 2 private networks PVLAN1 (1GB) and PVLAN2 (2GB) apart from your company network(1GB shared) in that case how to make sure that your application is using right network for the performance tests if not then how to use right network.
Sample Lab configurations: 

Operating System Hostname ip, 1Gbps (Company Network) Console  hostname idrac ip PVLAN 101 ip (3Gbps) PVLAN 102 ip (2 Gbps) PVLAN 103 ip (2 Gbps) Windows 2008 Enterprise R2 64 BIT Server WINPERF1 10.240.103.21 CONPERF1 10.240.103.101 192.168.101.1 NA 192.168.103.1 Windows 2008 Enterprise R2 64 BIT Server WINPERF2 10.240.103.22 CONPERF2 10.240.103.102 192.168.101.2 NA 192.168.103.2 Windows 2003 Enterprise R2 64 BIT Server WINPERF3 10.240.103.23 CONPERF3 10.240.103.103 192.168.101.3 192.168.102.1 NA Redhat 6 Advanced Server 64 Bit LINUXPERF1 10.240.103.31 CONPERF11 10.240.103.111 192.168.101.11 NA 192.168.103.11 Redhat 6 Advanced Server 64 Bit LINUXPERF2 NA CONPERF12 10.240.103.112 192.168.101.12 NA 192.168.103.12
Note:-iDRAC is Integrated Dell™ Remote Access Controller So now, I want that the communication between my DB which is hosted on WINPERF1 and my Application server which is at LINUXPERF1 should happen via PVLAN1(3Gbps) network. First how to check the current communication network? Ans:- Go to WINPERF1 and ping LINUXPERF1 this will give you reply from LINUXPERF1 via any one of  10.240.103.31(Company network), 192.168.101.11(PVLAN1) or 192.168.103.11(PVLAN2) this will tell you which network in used while communicating from LINUXPERF1 to WINPERF1. How to set the right network? 1. Change in the hosts file at windows server location C:\WINDOWS\system32\drivers\etc Add:- # This is for any connection coming on WINPERF1 will come via PVLAN1  192.168.101.1   WINPERF1 # This is for any connection going out from WINPERF1 to LINUXPERF1 will go via PVLAN1 192.168.101.11  LINUXPERF1 2. Change in the LINUXPERF1at /etc/hosts Add:-  # 192.168.101.11  LINUXPERF1 # 192.168.101.1   WINPERF1 Important Point:  1. If we want LINUXPERF1 to connect to DB via PVLAN1 and Client at WINPERF3 via PVLAN 3 this is not possible because PVLAN3 is not available for WINPERF1. 2. If we have a situation where LINUXPERF1 need to communicate with LINUXPERF2 via say PVLAN3 then following changes in hosts file of both of these machines.
In Machine LINUXPERF1
192.168.103.11     LINUXPERF1_ha (_ha is used because LINUXPERF1 is already using 192.168.101.11  LINUXPERF1 for communication with WINPERF1)
192.168.103.12      LINUXPERF2

In Machine LINUXPERF2
192.168.103.12   LINUXPERF2
 192.168.103.11     LINUXPERF1_ha
 note:- LINUXPERF2 should address LINUXPERF1 as LINUXPERF1_ha


Sample Performance Lab Setup

http://www.gliffy.com/go/publish/4816255/