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Given the limited host ports available on a ME5, attaching the storage system and hosts to a SAN allows more hosts to connect to a single storage system concurrently. While this can significantly improve the usage efficiency of the storage system, administrators should carefully balance the total workload driven by all connected hosts and the resource availability on the storage system.
When connecting to the storage system using FC switches, use Fibre Channel zones to segment the fabric to restrict access and isolate traffic. A zone contains paths between initiators (server HBAs) and targets (storage array front-end ports). Either physical ports (port zoning) on the Fibre Channel switches or the WWNs (name zoning) of the end devices can be used in zoning. The following list includes key zoning rules and recommendations.
Zoning Fibre Channel switches for Linux hosts is essentially no different than zoning any other hosts to the ME5 Series storage system. The following list includes key zoning rules and recommendations.
Note: Dell Technologies recommends using name zoning and creating single-initiator, multiple-target zones.
The Linux host FC initiator WWNs are required for FC zoning and creating the host connection on the ME5 storage system.
Create and run the following bash shell script to identify the HBA WWNs on the Linux host. The fcshow.sh script is provided as an example to extract the host HBA information.
# cat fcshow.sh
#!/bin/bash
printf "%-10s %-20s %-10s %-10s %-28s %-s\n" "Host Port" "WWPN" "State" "Cur Speed" "Supported Speeds" "Port Type"
printf "%115s\n" |tr ' ' -
ls -1d /sys/class/fc_host/host* | while read host
do
port_name=`cat $host/port_name`
port_state=`cat $host/port_state`
port_speed=`cat $host/speed`
port_type="`cat $host/port_type`"
supported_speeds="`cat $host/supported_speeds`"
printf "%-10s %-20s %-10s %-10s %-28s %-s\n" ${host##*/} $port_name $port_state "$port_speed" "$supported_speeds" "$port_type"
done
# bash fcshow.sh
Host Port WWPN State Cur Speed Supported Speeds Port Type
-------------------------------------------------------------------------------------------------------------------
host11 0x2100f4e9d4561392 Online 16 Gbit 8 Gbit, 16 Gbit, 32 Gbit NPort (fabric via point-to-point)
host12 0x2100f4e9d4561393 Online 16 Gbit 8 Gbit, 16 Gbit, 32 Gbit NPort (fabric via point-to-point)
Locate the ME5 host port WWN information in the PowerVault Manager or by running the interactive CLI command. See Dell PowerVault ME5 Series Storage System CLI Reference Guide on Dell.com/support for a detailed explanation of all available CLI commands.
Identify WWNs using PowerVault Manager
Identifying WWNs using interactive CLI commands
# ssh manage@{controller-IP-address}
# show ports detail
# show ports detail
Ports Media Target ID Status Speed(A) Speed(C) Health Reason Action
----------------------------------------------------------------------------------------
A0 FC(P) 207000c0fff03b1e Up 16Gb Auto OK
Topo(C) PID SFP Status Part Number Supported Speeds
------------------------------------------------------------------
PTP N/A OK FTLF8532P4BNV-E5 8G,16G,32G
A1 FC(P) 217000c0fff03b1e Up 16Gb Auto OK
Topo(C) PID SFP Status Part Number Supported Speeds
------------------------------------------------------------------
PTP N/A OK FTLF8532P4BNV-E5 8G,16G,32G
……. Truncated for brevity
Ports Media Target ID Status Speed(A) Speed(C) Health Reason Action
----------------------------------------------------------------------------------------
B0 FC(P) 247000c0fff03b1e Up 16Gb Auto OK
Topo(C) PID SFP Status Part Number Supported Speeds
------------------------------------------------------------------
PTP N/A OK FTLF8532P4BNV-E5 8G,16G,32G
B1 FC(P) 257000c0fff03b1e Up 16Gb Auto OK
Topo(C) PID SFP Status Part Number Supported Speeds
------------------------------------------------------------------
PTP N/A OK FTLF8532P4BNV-E5 8G,16G,32G
--- Truncated for brevity
The following iSCSI network best practices are recommended:
See Dell PowerVault ME5 Series Storage System Deployment Guide for additional iSCSI best-practice information.
The iSCSI port network information can be found under the Settings > iSCSI > Host Ports and Configuration in the PowerVault Manager. See Figure 3 and Figure 4.
Alternatively, use the ME5 interactive CLI command to display the port information.
# ssh manage@{controller-IP-address}
# show ports detail
Ports Media Target ID Status Speed(A) Health Reason Action
---------------------------------------------------------------------------------------------------------
A0 iSCSI iqn.1988-11.com.dell:01.array.bc305bf03b18 Up 10Gb OK
Port Details
------------
IP Version: IPv4
IP Address: 10.10.xxx.xxx
Gateway: 0.0.0.0
Netmask: 255.255.0.0
MAC: 00:C0:FF:5C:B0:23
SFP Status: OK
Part Number: D0R73
10G Compliance: Special
Ethernet Compliance: N/A
Cable Technology: Passive
Cable Length: 2
…… Truncated for brevity
B0 iSCSI iqn.1988-11.com.dell:01.array.bc305bf03b18 Up 10Gb OK
Port Details
------------
IP Version: IPv4
IP Address: 10.10.xxx.xxx
Gateway: 0.0.0.0
Netmask: 255.255.0.0
MAC: 00:C0:FF:5C:AC:1F
SFP Status: OK
Part Number: D0R73
10G Compliance: Special
Ethernet Compliance: N/A
Cable Technology: Passive
Cable Length: 2
…… Truncated for brevity
The Linux host requires at least one HBA port configured on the iSCSI network. For redundancy, configure dual iSCSI networks on the Linux host and the ME5 storage system. The following table shows an example of the redundant iSCSI network.
iSCSI Networks | Linux network interfaces | ME5 iSCSI ports |
VLAN 1 | eth1 | A0, B0 |
VLAN 2 | eth2 | A1, B1 |
If using jumbo frames, ensure that the Linux iSCSI network interfaces have the proper setting for the MTU size. Typically, the network interface configuration files are in the /etc/sysconfig/network-scripts or /etc/sysconfig/network directory. An example of the interface file is shown below.
DEVICE=eth1
STARTMODE=onboot
USERCONTROL=no
BOOTPROTO=static
NETMASK=255.255.0.0
IPADDR=10.10.xxx.xxx
MTU=9000
To test the interface with the new setting, use ping with the -M do -s {packet size} arguments.
# ping -M do -s 8972 -c 3 10.10.xxx.xxx (ME5 iSCSI port IP)
To configure the host iSCSI initiator, use the following steps to make the recommended settings and activate the iSCSI transport.
Red Hat
# dnf install iscsi-initiator-utils
# systemctl enable iscsi --now
SUSE
# zypper install open-iscsi
# systemctl enable iscsi --now
# iscsi-iname
# vi /etc/iscsi/initiatorname.iscsi
InitiatorName={output of iscsi-iname}
node.session.timeo.replacement_timeout = 5
node.session.cmds_max = 1024
node.session.queue_depth = 128
# iscsiadm -m discovery -t st -p {ME5_A0_IP} -discover
# iscsiadm -m node –L all
# iscsiadm -m node
{ME5-A0-IP}:3260,1 iqn.1988-11.com.dell:01.array.bc305bf03b18
{ME5-A1-IP}:3260,3 iqn.1988-11.com.dell:01.array.bc305bf03b18
{ME5-B0-IP}:3260,2 iqn.1988-11.com.dell:01.array.bc305bf03b18
{ME5-B1-IP}:3260,4 iqn.1988-11.com.dell:01.array.bc305bf03b18
Kernel parameters that can be tuned for performance are found in the /proc/sys/net/core and /proc/sys/net/ipv4 kernel parameters. When you have determined the optimal values, permanently set these parameters 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.core.netdev_max_backlog | 300000 | Maximum number of incoming connections backlog queue |
net.ipv4.tcp_rmem | 4096 87380 134217728 | Auto-tuned 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-tuned TCP buffer limits: min, default, and max size of the send buffer used by each TCP socket |
net.ipv4.tcp_moderate_rcvbuf | 1 | Auto-tuned TCP 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 |
After configuring the FC zones or iSCSI initiators, add the Linux hosts on the ME5 storage system.
Note: If the Create Host button remains gray instead of blue, it means that the storage system does not have any visible connections to the host initiators. Verify the host connections, FC zones, iSCSI initiator configuration, and switch configuration and correct the issues.