iSCSI on Debian/Ubuntu - Network Configuration

Ubuntu Server (18.04+): netplan

• YAML-based configuration
• Default for Ubuntu Server
• Managed by systemd-networkd or NetworkManager

Debian / Ubuntu Desktop: NetworkManager

• GUI and CLI management
• Dynamic configuration
• Good for desktop environments

Debian Traditional: /etc/network/interfaces

• Text-based configuration
• Simple and reliable
• Good for servers

Create netplan configuration:

# Create netplan config for storage interfaces
sudo tee /etc/netplan/60-storage.yaml > /dev/null <<'EOF'
network:
  version: 2
  renderer: networkd
  ethernets:
    ens1f0:
      dhcp4: no
      dhcp6: no
      addresses:
        - 10.100.1.101/24
      mtu: 9000
      optional: true
    ens1f1:
      dhcp4: no
      dhcp6: no
      addresses:
        - 10.100.2.101/24
      mtu: 9000
      optional: true
EOF

# Apply configuration
sudo netplan apply

# Verify
ip addr show ens1f0
ip addr show ens1f1

Key netplan parameters:

• dhcp4: no - Static IP configuration
• mtu: 9000 - Jumbo frames
• optional: true - Don't wait for interface during boot (if not critical)

Traditional Debian configuration:

# Edit /etc/network/interfaces
sudo tee -a /etc/network/interfaces > /dev/null <<'EOF'

# Storage interface 1
auto ens1f0
iface ens1f0 inet static
    address 10.100.1.101
    netmask 255.255.255.0
    mtu 9000
    post-up ethtool -G ens1f0 rx 4096 tx 4096 || true
    post-up ethtool -C ens1f0 rx-usecs 50 tx-usecs 50 || true

# Storage interface 2
auto ens1f1
iface ens1f1 inet static
    address 10.100.2.101
    netmask 255.255.255.0
    mtu 9000
    post-up ethtool -G ens1f1 rx 4096 tx 4096 || true
    post-up ethtool -C ens1f1 rx-usecs 50 tx-usecs 50 || true
EOF

# Restart networking
sudo systemctl restart networking

# Or bring up interfaces individually
sudo ifup ens1f0
sudo ifup ens1f1

# Verify MTU
ip link show ens1f0 | grep mtu

# Test MTU (jumbo frames)
ping -M do -s 8972 <storage_portal_ip>

# If ping fails, check:
# 1. Interface MTU
# 2. Switch MTU configuration
# 3. Storage array MTU