ISCSI Multipath on ESXI host

[zeeshan qadir]

Hi everyone,

Please consider the following example:

Below ESXI is using ISCSI adapter mapped to VMK1 and VMk2 for Multi path.

ESXI   VMK1 10.1.1.1. VSW0-VMNIC1----------10.1.1.111 ISCSI TARGET-LUN0

             VMK2 10.1.1.1.2 VSW1-VMNIC2-------|

1) Let say ESXI has to perform write operation for 2000K bytes on LUN0. Will ESXI send some data for this write operation on one path say VMK1 ( 10.1.1.1--10.1.1.111) and send some data over

VM2 ( 10.1.1.2--10.1.1.111) ? or only one path is used actively while the other path is for redundancy purpose only?

2) How does ESXI keep track if the path to target  is available? Does it use some  Keep alive to detect  path failure and move the traffic to other available path?

Thanks and have a nice weekend!!

[NathanosBlightc]

Based on VMware documentary to use multipath on ESXi hosts you should consider following points:

1. Enable vmknic-based software iSCSI multipathing

2. Create 2 VMkernel port groups and connect one uplink to each of them.

3. Bind each VMkernel network adapter to the software iSCSI adapter and run a rediscovery of iSCSI targets to detect multiple paths to them.

4. Enabling multipathing removes the ability to route to storage. So the iSCSI target and the VMkernel port (initiators) must have an IP address in the same network.