The following iSCSI network best practices are recommended:
Network/VLAN | iSCSI HBA port | ME4 Series iSCSI ports | |
All-iSCSI port configuration | FC/iSCSI port configuration | ||
Network 1/VLAN 1 | eth0 | A0, B0, A2, B2 | A2, B2* |
Network 2/VLAN 2 | eth1 | A1, B1, A3, B3 | A3, B3* |
*In an FC/iSCSI configuration, only ports A2, A3, B2, and B3 are available. Ports A0, A1, B0, and B1 are reserved for FC.
If the iSCSI ports are set up during the initial Easy Start wizard, the iSCSI port network information can be found under the Home topic in ME Storage Manager. Hover over the iSCSI port to see the configuration information. See Figure 2.
Alternatively, use the ME4 Series CLI command to display the port information.
# ssh manage@IP-address
# show ports detail
Ports Media Target ID Status Speed(A) Health Reason Action
-----------------------------------------------------------------------------------------------------
A2 iSCSI iqn.1988-11.com.dell:01.array.bc305bf03b17 Up 10Gb OK
Port Details
------------
IP Version: IPv4
IP Address: 10.10.61.12
Gateway: 0.0.0.0
Netmask: 255.255.0.0
MAC: 00:C0:FF:47:68:68
SFP Status: OK
Part Number: 616740002
10G Compliance: Special
Ethernet Compliance: 0x00
Cable Technology: Passive
Cable Length: 2
To configure the host iSCSI initiator, use the following steps to make the recommended settings and activate the iSCSI transport.
node.session.timeo.replacement_timeout = 5
node.session.cmds_max = 1024
node.session.queue_depth = 128
# iscsiadm -m discovery -t st -p $ME4_A2_IP
# iscsiadm -m node –L all
# iscsiadm -m node
10.10.61.12:3260,5 iqn.1988-11.com.dell:01.array.bc305bf03b17
10.20.61.12:3260,6 iqn.1988-11.com.dell:01.array.bc305bf03b17
10.20.61.13:3260,7 iqn.1988-11.com.dell:01.array.bc305bf03b17
10.10.61.13:3260,8 iqn.1988-11.com.dell:01.array.bc305bf03b17
# cat /etc/iscsi/initiatorname.iscsi
Kernel parameters that can be tuned for performance are found in the /proc/sys/net/core and /proc/sys/net/ipv4 kernel parameters. When optimal values are determined, permanently set these in the /etc/sysctl.conf file. Like most other modern operating system platforms, Linux can efficiently auto-tune TCP buffers. However, by default, some settings such as buffer size are conservatively low. Experimenting with the following kernel parameters can lead to improved network performance, and subsequently improve iSCSI performance.
To set these parameters permanently, enter them in the /etc/sysctl.conf file and reboot the servers.
Parameter | Value | Description |
net.core.rmem_max | 134217728 |
Maximum receive buffer size used by each TCP socket |
net.core.wmem_max | 134217728 | Maximum send buffer size used by each TCP socket |
net.ipv4.tcp_rmem | 4096 87380 134217728 | Auto-tune TCP buffer limits: min, default, and max size of the receive buffer used by each TCP socket |
net.ipv4.tcp_wmem | 4096 65536 134217728 | Auto-tune TCP buffer limits: min, default, and max size of the send buffer used by each TCP socket |
net.core.netdev_max_backlog | 300000 | Maximum number of incoming connections backlog queue |
net.ipv4.tcp_moderate_rcvbuf | 1 | Auto-tune the receiver buffer size |
net.bridge.bridge-nf-call-iptables | 0 | netfilter |
net.bridge.bridge-nf-call-arptables | 0 | netfilter |
net.bridge.bridge-nf-call-ip6tables | 0 | netfilter |