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May 29th, 2014 10:00
VMware - iSCSI - VNX - Port Binding Question - Single Subnet vs. Multiple Subnets
Hello,
I recently read through the new technical note from EMC called "VMware ESX 5.x iSCSI NMP Connectivity Guide for VNX", P/N 302-001-019, May 2014, and it seems to contradict with the "EMC Host Connectivity Guide for VMware ESX Server", P/N 300-002-304, February 2014. I am trying to determine which guide is "correct."
EMC Host Connectivity Guide for VMware ESX Server:
Page 55: "EMC recommends having the two NICs/ VMkernel ports are on different subnets. Ensure the SP ports belonging to the same Storage Processor are also on different subnets."
The diagram shows multiple subnets, and then on page 59 the instructions show how to configure port binding of these vmkernels.
This is how EMC has recommended iSCSI to be configured for the last 3+ years. It also matches VMware recommendations and several other storage vendors.
VMware ESX 5.x iSCSI NMP Connectivity Guide for VNX:
This guide uses the phrase "explicit port binding" to refer to traditional iSCSI port binding as described above. However, this guide says (on page 7):
"Port Binding can only be used when the initiator and all targets are part of a single subnet."
The figure on page 7 says that port binding is "Not recommended" and it goes on to say that using a single network address space (subnet) is "not recommended" (page 14).
The guide goes on to show how to configure "non port binding" (which the author calls "implicit port binding"), in which we are instructed NOT to configure the "Network Configuration" tab in the VMware iSCSI Initiator... i.e. no port binding.
This is contrary to the instructions provided in the Host Connectivity Guide, as well as VMware documentation, and all instructions from EMC to date.
Does anyone have more information as to which guide is "correct"?
sullybags
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May 29th, 2014 23:00
the newer document would be correct. i assume the older one will be updated eventually.
this change it to be in line with the following vmware kb:
http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2038869
addressing broadcast domains.
boyler05
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May 30th, 2014 07:00
Dave,
Thanks for the informative response. I was not aware of the VMware KB article you mentioned, especially since it contradicts the most current EMC Host Connectivity Guide for ESX, as well as the most current "Using EMC VNX Storage with VMware vSphere" TechBook (h8229). This is really good to know. I've set up a number of VNX systems using the "old method", which appears to be unsupported by VMware at this time. I presume EMC's current recommendation is to go back and re-configure all existing setups that are still using the EMC legacy iSCSI port binding with multiple subnets approach? Best practice is currently to use multiple subnets without port binding, correct?
sullybags
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May 30th, 2014 07:00
Absolutely , that is correct.
I’ve dealt with this issue for some time now and its good we finally have some updated documentation around the issue.
So basically, if there is multi-subnets = no port binding.
Same applies for other vendors, Dell / HP ect…
boyler05
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June 12th, 2014 13:00
Dave,
One follow-up question. I just wanted to verify that we are still supposed to set up a 1-to-1 mapping between each vmkernel and each physical vmnic on the ESXi host. In the example of a 10 GigE server, with a single vSwitch consisting of (2) physical uplinks (vmnic0 and vmnic1), we would configure the "iSCSI1" vmkernel with vmnic0 as "Active" and vmnic1 as "Unused"; and similarly we would configure the "iSCSI2" vmkernel with vmnic1 as "Active" and vmnic0 as "Unused"; correct? This is basically the same way we've always done it, but the key difference is that we don't add the vmkernels to the port binding screen in the iSCSI software initiator, correct?
Thanks again,
Bill
mkee
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July 1st, 2014 05:00
Thanks guys. This doc P/N 302-001-019, May 2014 is probably the most comprehensive I have seen on iSCSI configuration for VMware/VNX. Is there a similar doc for the VNXe? VMware configuration would be the same as described above and VMware KB: Considerations for using software iSCSI port binding in ESX/ESXi would still apply, however, I'm curious of iSCSI server configuration on the VNXe side. Specifically, assuming the IO expansion module is utilized and when configuring 4 ports/SP for iSCSI.
This is a good thread which describes utilizing 2 ports/SP and I believe to still be accurate.
Best Practice Setting up VNXe 3150 | VMware Communities
Do we have an updated version of P/N 302-001-019, May 2014 for the VNXe?
Thanks
Mike
Willing
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August 26th, 2014 13:00
Hi Dave,
This is a great topic. I have worked across most storage platforms using different fabrics. With regard to this VMware port binding used for only one subnet. I may be wrong but I believe this has to be contextual. I have implemented many storage solutions where a storage system has 2 SP with 2 subnets used between each for target networks. e.g SP1 p1 192.168.1/24,p2 192.168.5/24..SP2 p1 192.168.1/24, p2 192.168.5/24. From ESXi configured two separate iSCSI vswitches with one vmnic respective to each target subnet. Dual redundancy from ESXi to switch to Storage throughout. I have used port binding easily with expected 4 paths per device in Storage AA mode. Path failover and failback works perfect.
They say no binding for different subnets and routing. But bear in mind you can have communication from VMware iSCSI vmk ports to SAN with different subnets by use of vlan switch ports and dedicated switches without routing just fine. Also if two iSCSI vmnics per vswitch are used for each vmkernel then I don't see why we can't make use by path failover of both the vmnics configured by port binding.
I would appreciate your thoughts on this. Thank you
padukone
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August 30th, 2014 11:00
Hi All-
I'm trying to implement a similar scenario and want to use below example for my set up. Do you see anything wrong with this?
Willing
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September 2nd, 2014 07:00
gpaduk as this thread is closed, I am going to open a new thread on this. Jump on there
and paste back image. And yes that design looks fine. It's just that from the revised KB it is not recommended to port bind with such design which I have configured otherwise just fine and would like inputs on.