Can vSAN and iSCSI share a VDS and its uplinks?

[lucasjb]

Hi Communities,

I have two vSAN clusters under one vCenter Server sharing a VDS. I want to use the vSAN iSCSI Target Service to access some of each cluster's vSAN storage from the other cluster. Using the vSAN VDS I added two new port groups iSCSI1 and iSCSI2 (in addition to the vSAN port group with the vSAN vmk with teamed uplinks), assigned each one an Active uplink (set the other uplink to Unused) and created a vmk in each port group then setup Network Port Binding for my iSCSI Software Adapter to use these vmks. I configured two targets for Dynamic Discovery and Rescan Adapter. This populates the Static Discovery list with two targets as expected including the correct IQNs, however the Network Port Binding tab shows Path Status: Not used which I guess is bad. Also no Devices or Paths are discovered. I wonder if it's sending its iSCSI discovery out the vSAN vmk...

Could this work? Should this work?

[IRIX201110141]

It will work. We have the same kind of setup. Please consider the use of VLANs for better separation.

Regards,
Joerg

[lucasjb]

Thanks Joerg, I'm re-arranging my networking to separate the traffic with VLANs before I try again.

[bryanvaneeden]

Hi @lucasjb ,

I think this will work, VDS and uplink wise. But I'm pretty sure this isn't supported. Have a look at:

https://docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.vsphere.virtualsan.doc/GUID-13ADF2FC-9664-4...

Note:vSAN iSCSI target service does not support other vSphere or ESXi clients or initiators, third-party hypervisors, or migrations using raw device mapping (RDMs).

As far as I know you can't use vSAN ISCSI luns on a ESXi host. Please be aware of this.

[lucasjb]

Thanks @bryanvaneeden I hadn't read that closely enough. I'm still going to give it a try seeing as @IRIX201110141  claims that it can work, but I'll be sure not to rely on it for critical applications.

[IRIX201110141]

Stoppp...

vSAN  it self can offer a iSCSI target(s) but thats not what iam talking about.  My understanding is that the OP wanna to attached iSCSI stroage to the ESXi on the same NICs which are used by vSAN.

We have vSAN and Compellent together with our vMotion, LAN and so on together within the same fabric because we only have 2x10G or 2x25G.

Regards,
Joerg

[bryanvaneeden · Accepted solution]

@lucasjb No problem at all. Please see the reply from @IRIX201110141 since he just said that he misread your original question.

So please do be aware like I said that this isn't supported, or possibly not even possible to configure, hence the errors you are seeing. I would strongly advise against it if it works.

What might interest you is the following: vSAN HCI Mesh

This got introduced in vSphere 7 U1 and you can review the following blogposts to know a bit more about how it works:

https://blogs.vmware.com/virtualblocks/2020/09/16/introducing-vmware-vsan-hci-mesh/

https://vcloudvision.com/2020/09/15/introducing-vmware-vsphere-and-vsan-7-update-1-and-vcf-4-1/#VMwa... 

With this you can remotely attach "left-over" vSAN storage to another vSAN environment.

[depping]

Please note, HCI Mesh (mounting a datastore remotely) only works when you have:

- a local vSAN datastore

- both clusters are licensed with vSAN Enterprise license! 

I published a post on HCI Mesh considerations here:  http://www.yellow-bricks.com/2020/10/07/vsan-hci-mesh-considerations/

[lucasjb]

Thanks all, I won't pursue this configuration further. I don't have the required licensing for HCI Mesh, I also need to provide a storage solution for a third, non-vSAN enabled cluster, so I'll look for something that can serve all three.