VSAN Strectched Cluster - Host Isolation not working / Inaccessible VM

[TolgaAsik]

Hello,

My configuration is below:

* VSAN strecthed cluster (Site A - preffered / Site B -secondary)

* Witness in different network over WAN (L3)

* 4 uplinks ( 2 nic for management/VM traffic + 2 nic for VSAN dedicated)

* VSAN is in different VDS

* 4 host isolation (das.isolationAddress0-3) and das.useDefaultIsolationAddress=false

* 40 gig networks

* vmk2 for VSAN (non-routed network), vmk1 (vmotion-non-routed), vmk0 (management/VM and Witness connection) for ESXi hosts

I am testing "VSAN NICs are down" in SiteA-preffered ESXi host, but management/Witness connection continues.

In this situation I set host isolation response=shutdown, but no success. All VMs in Site A and Site B become inaccessible. Also Witness communication continues, becuase it is using other uplinks to communicate with Witness.

If I tested vice versa, "VSAN NIC are down" in Site B-secondary ESXi hosts, All VMs are powered off, and they are powering up on Site A, as desired.

I found the issue in FDM logs of ESXi hosts in SiteA, it is maneully setting again default gateway.

Why?

Is it a split-brain prevention control? But I am saying to VSAN, if you lost communication between sides, plesae shut down VMs. Site B is doing that, but why Site A is not doing.

[tayfundeger]

Hi,

Are you sure to define IP from Site A and Site B when specifying isolation address "vSphere HA - Advanced Settings"?

VMware recommends specifying two additional isolation response addresses, and each of these addresses should be site-specific. In other words, select an isolation response IP address from the Preferred Site and another isolation response IP address from the Non-Preferred Site. The vSphere HA advanced setting used for setting the first isolation response IP address is das.isolationaddress0 and it should be set to an IP address on the vSAN network which resides on the one site. The vSphere HA advanced setting used for adding a second isolation response IP address is das.isolationaddress1 and this should be an IP address on the vSAN network that resides on the alternate site.

Thanks.

[depping]

So you have 4 isolation addresses? What are they? We need to know a bit more than the info you provide. There's definitely something strange in your configuration if even the VMs in the location which is not impacted go inaccessible. Maybe a diagram would help

[TolgaAsik]

Hİ Tayfun,

Exactly, IPs are from different sites. two from switches in Site A, other two from switches in Site B.

[TolgaAsik]

Hi Duncan,

These IP adresses are defined on server switches where are directly connected to hosts. Diagram is ready, I am sending you.

By the way I created a ticket to VMware GSS, also they are analyzing the case, but little bit strange issue.

Thanks for interested.

[depping]

Following up via email