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SGT_Lindy
1 Copper

iSCSI MPIO and subnets

Is it OK to have all of my storage and hosts on the same subnet?

I see documentation from Dell that shows screen shots of Equallogic setup's with all interfaces on the same subnet. I am ok with this, actually would rather do it that way but Microsoft documentation states you should use seperate subnets for each host interface.

Example of samesubnet would be Storage IP's of say 10.50.1.2 and 10.50.1.1 and then a host server with 2 NIC's (Windows 2008 R2 with MPIO enabled) with IP's of 10.50.1.10 and 10.50.1.11.

Example of multi-subnet would be Storage IP's of 10.50.1.1 and 10.50.2.1 and the host server with 10.50.1.10 and 10.50.2.10.

All of this would be isolated from normal LAN traffic.

What is the right way to do it? Does it matter with everything on the same subnet?

Thanks!
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3 Replies
SGT_Lindy
1 Copper

RE: iSCSI MPIO and subnets

I found my answer...the last bullet point.

EqualLogic MPIO Requirements
The following host port requirements must be met to use MPIO with EqualLogic SANs:
• At least two (2) Ethernet ports are required on each host.
• The host operating system must have a supported MPIO driver or service available.
• The ports used for MPIO cannot be “teamed” to other ports.
• The ports must be the same speed
• The ports must be assigned IP addresses on the same subnet

That info came from most recent version of the Dell Equallogic configuration guide.
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Moderator
Moderator

RE: iSCSI MPIO and subnets

Thanks for coming back & posting the answer SGT_Lindy.
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KiegKhan
1 Copper

RE: iSCSI MPIO and subnets

Good that you found your answer. As you get into iSCSI you will find that different solutions recommend different IP Subnet configuration, eg: Equalogic requires one subnet but the MD3xxx series requires separate subnets per NIC port.
If you set it up correctly you will get good results, but if you setup incorrectly you will find the performance will be sub-par or it will even cause errors. Keep researching your iSCSI solution so that you really understand it and you will see the reasons for the different IP Subnet solutions each device requires.
One thing to consider would be if you mix devices. Say you have the Equalogic now and then find that your budget does not stretch to accomodate your next device so you opt for a cheaper SAN. You might find they require different IP Subnet setup so make sure you factor that in, eg: you might need additional Server NICs to connect to the new IP Subnets.
Regards.
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