Hyper V how to dedicate a NIC for ISCSI only

GordonLiq used Ask the Experts™
I am planning to setup the Hyper V HA solution. with 2 Host and 1SAN.
each Host has 2 dual port NICs ,
Host 1
NIC2 : do not configure the IP , add to virtual network and then will have 2 virtual IP :, for VM1 and VM2

the MY SAN's IP is

will the ISCSI traffic been dedicated to NIC1?  becuase the NIC2 dont have physical IP address , it only get virtuals and used in VM.

I know that it is better to have 2 subnets , 1 subnet for VMs and 1 subnet for ISCSI . but I really dont know how big the performance will be different. network-configure.docx

Please see the attachment as example , I prefer to put them into single subnet and single domain , that will make the management easier. but worry about big performance lost .  
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Paul SolovyovskySenior IT Advisor
Top Expert 2008

You really should have a different subnet for iSCSI and Production, otherwise a broadcast storm or loop will take down your entire virtual machine infrastructure, I have seen it personally at many customers sites.

You also should use a separate nic for iSCSI (Hyper V requirement).

Do yourself a favor and purchase another two nics (4 port would be best) especially if you're clustering them and would want to have a heartbeat nic as well.  2 ports on iscsi allow you to do multipathing via MPIO and round robin ont the volume

Unless you want to have headaches down the road do this properly and you'll save time later..but that all depends on how much you value your job..if you fail to plan..you plan to fail.  iSCSI can be a windows driver since you'll be using MS iSCSI initiator.

My $.02


OK , I already has 4 ports each Host, so get other 4 port means 8 port each host. will this too much for just 3 vms runing on host?

please confirm me , if I put the 2 NIC in 2 subnet , is that means I dedicte one NIC for ISCSI?
I am not very clear how to do the dedicate.
Svet PaperovIT Manager
You will have much better performance if you dedicate a NIC to the iSCSI only:
 - need to be on separated VLAN and IP segments
 - set the Jumbo frames to 9000 or more on the NIC, the switchport and the iSCSI target
 - specify the source IP address of the dedicated NIC in the advanced options of the iSCSI Initiator

With that setup you will have a good disk performance of the VHD on iSCSI; otherwise you will suffer of I/O delays.
Network Engineer
To dedicate the NIC to iSCSI traffic, you need to unbind all protocols except TCP/IP from the NIC. The NIC should not have a gateway assigned. Uncheck register this connection in DNS.
Paul SolovyovskySenior IT Advisor
Top Expert 2008
In the iSCSI initiator don't choose quick connect, configure the settings manually and choose the initiaor and target IPs as needed.  This will ensure that you're connecting to the correct target with appropriate nic.  

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