Configure a Linux host with iSCSI network adapters
The following sections describe how to configure a Linux host with iSCSI network adapters:
Complete the
PowerVault Manager guided system and storage setup process.
Refer to the cabling diagrams within this guide before attaching a host to the storage system; careful planning ensures a successful deployment.
Administrative or privileged user permissions are required to make system-level changes. The following sections assume root level access and that all required software packages are already installed, for example, iSCSI-initiator and DM Multipath.
Complete a planning worksheet with the iSCSI network IP addresses to be used, per the example in the following table.
Table 1. Example worksheet for single host server with dual port iSCSI NICsExample worksheet for dual port iSCSI NICs
Management
IP
Server Management
10.10.96.46
ME4024 Controller A Management
10.10.96.128
ME4024 Controller B Management
10.10.96.129
Subnet 1
Server iSCSI NIC 1
172.1.96.46
ME4024 controller A port 0
172.1.100.128
ME4024 controller B port 0
172.1.200.129
ME4024 controller A port 2
172.1.102.128
ME4024 controller B port 2
172.1.202.129
Subnet Mask
255.255.0.0
Subnet 2
Server iSCSI NIC 1
172.2.96.46
ME4024 controller A port 1
172.2.101.128
ME4024 controller B port 1
172.2.201.129
ME4024 controller A port 3
172.2.103.128
ME4024 controller B port 3
172.2.203.129
Subnet Mask
255.255.0.0
The following instructions document IPv4 configurations with a dual switch subnet for network redundancy and failover. It does not cover IPv6 configuration.
Attach a Linux host with iSCSI network adapters to the storage system
Ensure that all network adapters have the latest supported firmware and drivers
as described in the
Dell PowerVault ME4 Series Storage System Support Matrix
on the Dell Support web site..
Use the iSCSI cabling diagrams to cable the host servers to the switches or directly to the storage system.
Assign IP addresses for each network adapter connecting to the iSCSI network
CAUTION:The IP addresses must match the subnets for each network, so ensure that you correctly assign IP addresses to the network adapters. Assigning IP addresses to the wrong ports can cause connectivity issues.
NOTE:If using jumbo frames, they must be enabled and configured on all devices in the data path, adapter ports, switches, and storage system.
For RHEL 7
From the server terminal or console, run the
nmtui command to access the NIC configuration tool (NetworkManager TUI).
Select
Edit a connection to display a list of the Ethernet interfaces installed.
Select the iSCSI NIC that you want to assign an IP address to.
Change the IPv4 Configuration option to
Manual.
Using the planning worksheet that you created in the “Prerequisites” section, provide the subnet mask by entering the NIC IP address using the format x.x.x.x/16. For example: 172.1.96.46/16
Configure a gateway, if appropriate.
Select
IGNORE for the IPv6 Configuration.
Check
Automatically connect to start the NIC when the system boots.
Select
OK to exit Edit connection.
Select
Back to return to the main menu.
Select
Quit to exit NetworkManager TUI.
Ping the new network interface and associated storage host ports to ensure IP connectivity.
Repeat steps 1-12 for each NIC you are assigning IP addresses to.
For SLES 12
From the server terminal or console, run the
yast command to access the YaST Control Center.
Select
System > Network Settings.
Select the iSCSI NIC that you want to assign an IP address to, then select
Edit.
Select
Statically Assigned IP Address.
Using the planning worksheet that you created in the “Prerequisites” section, enter the NIC IP address. For example: 172.1.96.46
Using the planning worksheet that you created in the “Prerequisites” section, enter the NIC subnet mask. For example: 255.255.0.0.
Select Next.
Ping the new network interface and associated storage host ports to ensure IP connectivity.
Repeat steps 1-8 for each NIC you are assigning IP addresses to (NIC1 and NIC2 in the planning worksheet you created in the “Prerequisites” section).
Select
OK to exit network settings.
Select
OK to exit YaST.
Configure the iSCSI initiators to connect to the storage system
For RHEL 7
From the server terminal or console, run the following
iscsiadm command to discover targets (port A0):
Repeat the login for each controller host port using the discovery command output in step 1.
Reboot the host to ensure that all targets are automatically connected.
For SLES 12
From the server terminal or console, use the
yast command to access YaST Control Center.
Select Network
Service > iSCSI Initiator.
On the Service tab, select
When Booting.
Select the
Connected Targets tab.
Select
Add. The iSCSI Initiator Discovery screen displays.
Using the information from the worksheet you created earlier, enter the IP address for port A0 in the IP Address field, then click
Next. For example:
172.1.100.128.
Select
Connect.
On iSCSI Initiator Discovery screen, select the next adapter and then select
Connect.
When prompted, select
Continue to bypass the warning message, “Warning target with TargetName is already connected”.
Select Startup to Automatic, then click
Next.
Repeat steps 2-10 for all remaining adapters.
Once the targets are connected, click
Next > Quit to exit YaST.
Reboot the host to ensure that all targets are automatically connected.
Register the Linux host with iSCSI network adapters and create volumes
Log in to the
PowerVault Manager.
Access the Host Setup wizard:
From the Welcome screen, click
Host Setup.
From the Home topic, click
Action > Host Setup.
Confirm that you have met the listed prerequisites, then click
Next.
Type a hostname in the
Host Name field.
Select the iSCSI initiators for the host you are configuring, then click
Next.
Group hosts together with other hosts.
For cluster configurations, group hosts together so that all hosts within the group share the same storage.
If this host is the first host in the cluster, select
create a new host group, then provide a name and click
Next.
If this host is being added to a host group that exists, select
Add to existing host group. Select the group from the drop-down list, then click
Next.
NOTE:The host must be mapped with the same access, port, and LUN settings to the same volumes or volume groups as every other initiator in the host group.
For Stand-alone hosts, select the
Do not group this host option, then click
Next.
On the Attach Volumes page, specify the name, size, and pool for each volume, and click
Next.
To add a volume, click
Add Row. To remove a volume, click
Remove.
NOTE:Dell
recommends that you update the name with the hostname to better identify the volumes.
On the Summary page, review the host configuration settings, and click
Configure Host.
If the host is successfully configured, a
Success dialog box is displayed
Click
Yes to return to the Introduction page of the wizard, or click
No to close the wizard.
Enable and configure DM Multipath on the Linux host with iSCSI network adapters
NOTE:Safeguard and block internal server disk drives from multipath configuration files. These steps are meant as a basic setup to enable DM Multipath to the storage system. It is assumed that DM Multipath packages are installed.
Run the
multipath –t command to list the DM Multipath status.
If no configuration currently exists, use the command information displayed in step 1 to copy a default template to the directory
/etc.
If the DM multipath kernel driver is not loaded:
Run the
systemctl enable multipathd command to enable the service to run automatically.
Run the
systemctl start multipathd command to start the service.
Run the
multipath command to load storage devices in conjunction with the configuration file.
Run the
multipath –l command to list the
Dell PowerVault ME4 Series storage devices as configured under DM Multipath.
Create a Linux file system on the volumes
Perform the following steps to create and mount an XFS file system:
From the multipath –l command output above, identify the device multipath to target creating a file system.
In this example, the first time multipath is configured, the first device will be
/dev/mapper/mpatha, which corresponds to
sg block devices
/dev/sdb and
/dev/sdd.
NOTE:Run the
lsscsi command to list all SCSI devices from the Controller/Target/Bus/LUN map. This also identifies block devices per controller.
Run the
mkfs.xfs/dev/mapper/mpatha command to create an xfs type file system.
Run the
mkdir/mnt/VolA command to create a new mount point for this file system with a referenced name, such as VolA.
Run the
mount /dev/mapper/mpatha /mnt/VolA command to mount the file system.
Begin using the file system as any other directory to host applications or file services.
Repeat steps 1-5 for other provisioned volumes from the
PowerVault Manager. For example,
/dev/mapper/mpathb corresponds to
sg block devices
/dev/sdc and
/dev/sde.
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