DB2 10 for Linux on System z Using z/VM v6.2, Single System Image Clusters and Live Guest Relocation

Chapter 6. Networking 65

6.4.1 Environment

Figure 6-3 illustrates the setup and relocation scheme.

Figure 6-3 Environment, with indication of where itsolnx4 is relocated to

System environment

򐂰 Member 1 of SSI cluster z/VM - node itsossi1, 30 GB memory

򐂰 Member 3 of SSI cluster z/VM - node itsossi3, 30 GB memory

򐂰 Member 4 ofSSI clust - z/VM - node itsossi4, 8 GB memory

򐂰 Guest 1 - node itsolnx1 (IP address 9.12.5.118), 20 GB virtual memory

򐂰 Guest 2 - node itsolnx4 (IP address 9.12.5.119), 20 GB virtual memory

򐂰 DB2 DB resides on guest 2 - approximately 510,000 records, each record with

approximately 3000 bytes

򐂰 SQL queries on guest 1: select * from table name

6.4.2 Tests

Test scenarios running a SELECT query

Linux on System z guest named ITSOLNX1 had its DB2 configured to access the remote

database of ITSOLNX4, so that a SELECT query could be run from ITSOLNX1 to retrieve

data from ITSOLNX4. In Example 6-12 , we enabled access to ITSOLNX4’s database from

ITSOLNX1.

Example 6-12 Enabling access to remote database

db2inst1@itsolnx1:~> db2 catalog tcpip node itsolnx4 remote 9.12.5.119 server

60004 remote_instance db2inst1 ostype Linux

db2inst1@itsolnx1:~> db2 catalog database sample as “rsample” at node itsolnx4

db2inst1@itsolnx1:~> db2 connect to rsample USER db2inst1 USING db2inst1

z10

itsolnx1

itsolnx4

z196

CPC

CPC

ITSOSSI1

ITSOSSI2

ITSOSSI3

ITSOSSI4

30GB

8GB

8GB

30GB

Tests 3 and 4

Tests 5 and 6

66 DB2 10 for Linux on System z Using z/VM v6.2, SSI Clusters and LGR

The MTU size was set using the IP utility, as shown in Example 6-13.

Example 6-13 Setting the MTU to 8992 on the Linux guests

# on guest 1

itsolnx1:~ # ip link set dev eth1 mtu 8992

# on guest 2

itsolnx4:~ # ip link set dev eth1 mtu 8992

The SQL query shown in Example 6-14 was then run for each test, prefixed with “time”, to

check how long the query took to run. The results are presented on Table 6-2.

Example 6-14 SQL query run during the tests

db2inst1@itsolnx1:~> time db2 “select * from tablename” >/dev/null

The following were the tests we performed:

1. Test1 - Both guests reside on member 1. MTU size set to 1492 on both guests. Guest 1

issues the SQL query command.

2. Test2 - Both guests reside on member 1. MTU size set to 8992 on both guests. Guest 1

issues the SQL query command.

3. Test3 - Both guests reside on member 1. MTU size is set to 1492. Guest 2 is relocated to

member 3 while guest 1 issues the SQL query command.

4. Test4 - Both guests reside on member 1. MTU size is set to 8992. Guest 2 is relocated to

member 3 while guest 1 issues the SQL query command.

5. Test5 - Both guests reside on member 1. MTU size is set to 1492. Guest 2 is relocated to

member 4 while guest 1 issues the SQL query command.

6. Test6 - Both guests reside on member 1. MTU size is set to 8992. Guest 2 is relocated to

member 4 while guest 1 issues the SQL query command.

Table 6-2 Test results

Test scenarios running an SCP transfer

A file of approximately 900 MB was copied from guest 1 to guest 2 in each test, using the

command shown in Example 6-15. The results are presented in Table 6-3 on page 67.

Example 6-15 secure copy command executed during tests

db2inst1@itsolnx1:~> time scp largefile.img root@9.12.5.119:~/

Test # Guest From To MTU Time Relocation Processor

Load

1 itsoss4 itsossi1 itsossi1 8992 0m14.352s No 2

2 itsoss4 itsossi1 itsossi1 1492 0m13.186s No 2

3 itsoss4 itsossi1 itsossi3 8992 0m13.092s Yes 1

4 itsoss4 itsossi1 itsossi3 1492 0m13.713 Yes 1

5 itsoss4 itsossi1 itsossi4 8992 0m13.322 Yes 1

6 itsoss4 itsossi1 itsossi4 1492 0m14.010s Yes 1