IBM Cloud: VPC環境でのZone間/Region間におけるjumbo frame通信の確認

# 1. 設定

以下の設定を、全てのサーバーで実施

```txt:Jumbo Frameの有効化
[root@syasuda-webserver1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 02:00:03:02:70:58 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.7/24 brd 10.0.0.255 scope global dynamic eth0
       valid_lft 295sec preferred_lft 295sec
    inet6 fe80::3ff:fe02:7058/64 scope link
       valid_lft forever preferred_lft forever

[root@syasuda-webserver1 ~]# ip link set mtu 9000 dev eth0

[root@syasuda-webserver1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 9000 qdisc pfifo_fast state UP group default qlen 1000
    link/ether 02:00:03:02:70:58 brd ff:ff:ff:ff:ff:ff
    inet 10.0.0.7/24 brd 10.0.0.255 scope global dynamic eth0
       valid_lft 273sec preferred_lft 273sec
    inet6 fe80::3ff:fe02:7058/64 scope link
       valid_lft forever preferred_lft forever
```

# 2. IPアドレスの確認

以下の結果より、

- 10.0.0.7はjp-tok-1
- 10.1.0.7はjp-tok-2
- 10.100.0.5はjp-osa-1

```
[root@new-syasuda-tok1-vpc1 ~]# ibmcloud target -r jp-tok
[root@new-syasuda-tok1-vpc1 ~]# ibmcloud is ins | grep -e ID -e webserver
ID                                          Name                            Status    Reserved IP    Floating IP       Profile    Image                                           VPC                Zone       Resource group
02e7_8b5af102-578d-425b-ad9c-f878178196f0   syasuda-webserver1              running   10.0.0.7       -                 cx2-2x4    ibm-centos-7-6-minimal-amd64-2                  vpc-tok-syasuda1   jp-tok-1   Common
02f7_80c2007a-8e7f-409b-b749-d769cb161b41   syasuda-webserver2              running   10.1.0.7       -                 cx2-2x4    ibm-centos-7-6-minimal-amd64-2                  vpc-tok-syasuda1   jp-tok-2   Common

[root@new-syasuda-tok1-vpc1 ~]# ibmcloud target -r jp-osa
[root@new-syasuda-tok1-vpc1 ~]# ibmcloud is ins | grep -e ID -e syasuda-vsi-test2
ID                                          Name                                Status    Reserved IP     Floating IP     Profile    Image                                           VPC                Zone       Resource group
02n7_8257642e-794f-4817-8403-98498d5d70d1   syasuda-vsi-test2                   running   10.100.0.5      -               bx2-2x8    ibm-centos-7-9-minimal-amd64-7                  vpc-osa-syasuda    jp-osa-1   Default
```

# AZ間(jp-tok-1とjp-tok-2間）通信

```
[root@syasuda-webserver1 ~]# ping -M do -s 8972 10.1.0.7 -c 5
PING 10.1.0.7 (10.1.0.7) 8972(9000) bytes of data.
8980 bytes from 10.1.0.7: icmp_seq=1 ttl=57 time=1.43 ms
8980 bytes from 10.1.0.7: icmp_seq=2 ttl=57 time=1.54 ms
8980 bytes from 10.1.0.7: icmp_seq=3 ttl=57 time=1.52 ms
8980 bytes from 10.1.0.7: icmp_seq=4 ttl=57 time=1.63 ms
8980 bytes from 10.1.0.7: icmp_seq=5 ttl=57 time=1.53 ms

--- 10.1.0.7 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4006ms
rtt min/avg/max/mdev = 1.430/1.533/1.632/0.073 ms
```

# Region間(jp-tok-1とjp-osa-1間）通信

```
[root@syasuda-webserver1 ~]# ping -M do -s 8972 10.100.0.5 -c 5
PING 10.100.0.5 (10.100.0.5) 8972(9000) bytes of data.
8980 bytes from 10.100.0.5: icmp_seq=1 ttl=54 time=9.09 ms
8980 bytes from 10.100.0.5: icmp_seq=2 ttl=54 time=9.02 ms
8980 bytes from 10.100.0.5: icmp_seq=3 ttl=54 time=9.00 ms
8980 bytes from 10.100.0.5: icmp_seq=4 ttl=54 time=9.02 ms
8980 bytes from 10.100.0.5: icmp_seq=5 ttl=54 time=8.98 ms

--- 10.100.0.5 ping statistics ---
5 packets transmitted, 5 received, 0% packet loss, time 4004ms
rtt min/avg/max/mdev = 8.983/9.026/9.090/0.069 ms
```