VNXe 3200 - Questions about direct attached ESXi hosts over iSCSI

Question

Hello everyone,

the VNXe 3200 is my first EMC storage and I have a few questions about direct attached ESXi hosts over iSCSI.

I want to attach two ESXi 5.5 hosts directly over 10Gb Ethernet to the storage.

Let me tell you how I understand the procedure so far:

The manual says that every iSCSI target must have two IP addresses for HA. In Unisphere I can set two IP addresses for every 10Gb Ethernet port because the system sees the eight ports combined as for ports (4 on controller A, 4 on controller B), right? So the first address is for expample for Port 1 on controller A and the second address is for Port 1 on controller B.

If I had one or two 10Gb Switches then iSCSI would go over them. And the second address for port 1 on controller B would be passive as long as controller A is running.

But I want to attach the ESXi hosts directly to the storage, so Port 1 of the ESXi host wouldn´t be able to see Port 1 on controller B because its connected directly to Port 1 on controller A. Every host has two 10Gb Ethernet ports. So I just have to connect Port 1 on Controller A with Port 1 of an ESXi host. I cannot use Port 1 on controller B for Port 2 on the ESXi host, right? I have to connect it Port 2 of the ESXi host to Port 2 of controller B so the host sees both controllers.

And that leads to the next question: Do I need the PowerPath software on the ESXi hosts when they are NOT connected to the storage over switches? As far as I understand the PowerPath software is for scenarios where one ESXi Port can see at least two storage ports. For example ESXi Port 1 sees Storage Ports 1 on controller A and controller B and only switches from A to B, when A fails.

I´m sorry if I explained myself unclear. If you need additional information, please let me know.

Any help would be highly appreciated. So thanks in advance .

PAC-MAN · Accepted Answer

Both the configurations are valid. check this doc. https://support.emc.com/docu53338_VMware-ESX-5.x-iSCSI-NMP-Connectivity-Guide-for-VNX.pdf?language=en_US (Pg no 16)

EMC recommends Round Robin, the built in PSP's should work just fine but if you wish you can also use PowerPath for centralized management etc.

Hope this helps!

mark846 · Answer

I added a picture of my planned scenario. Please let me know if this is correct, thanks.

reedic · Answer

Hi mark846,

Welcome to the EMC family! I hope you are enjoying your new VNXe3200 storage system. The following documents would be good places to use as a reference for your desired setup.

Using a VNXe3200 System with VMware NFS or VMware VMFS

VNXe3200 High Availability

When setting up your iSCSI Interfaces (in the Unisphere GUI by navigating to the Settings > iSCSI Settings page), you can select the specific port that you would like to create the iSCSI Interface on. For example if you wanted to create an iSCSI Interface on Ethernet Port 3, you would select Ethernet Port 3 from the list and click the Create button. In the Create iSCSI Network Interface window that pops up, you would enter your networking information for Ethernet Port 3 on SPA and SPB. You would then repeat this process to create iSCSI Interfaces on another Ethernet port for your desired setup.

Once your iSCSI Interfaces are configured, you would be able to cable up your ESXi hosts to the VNXe3200 system. The picture you provided looks good. You just want to keep in mind that Block-level interfaces (iSCSI or FC) on the VNXe3200 do not failover, which is why you want a path to SPA and SPB for each ESXi host (more information on this can be found in the VNXe3200 High Availability white paper, link provided above). Because each of the ESXi hosts would have multiple connection paths to the VNXe3200 storage system (ESXi Host 1 has paths to SPA and SPB, and ESXi Host 2 has paths to SPA and SPB), you would need to use multipathing software on each ESXi host to manage the multiple paths to the VNXe3200.

Hopefully this helps point you in the right direction.

mark846 · Answer

Hi pac-man,thank you very much for the information. Gonna have to read the docs .

mark846 · Answer

Hi Charles,thanks a lot for this information!Please have a look on my second picture. Does this make any difference in configuration? Or is the result the same?I mean, are Port 1 on SPA and Port 1 on SPB two seperate iSCSI ports or do I have to see them as a kind of a group?Is there any technical difference between both configurations on the pictures?So do I have to license a MPIO software like PowerPath or can I handle it with the built-in path-policies of vSphere/ESXi? (fixed, MRU, RR)Regards, Mark

mark846 · Answer

For the last two days I did a lot of failover tests.

Is this common behaviour for this model that an iSCSI failover lasts about 30 seconds? In this time all VMs stop responding but the LUNs are still available for the ESXi hosts.

Would direct attached SAS be faster in handling failovers?

Also when I choose the path policy "Round Robin" only two of the four paths are in status "Active IO". Is this something I should worry about?

As far as I read in the documentation, VMware Knowledgebase, blogs etc. I shouldn´t use iSCSI port binding because of some issues like too much paths.

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2038869

VNX

VNXe 3200 - Questions about direct attached ESXi hosts over iSCSI

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