Hi All
I recently took over a vSAN environment with 2x Dell S4128 10Gb switches and 6 hosts running ESX 6.7u2 with 8 NICs each.
Originally the vSAN hosts were just connecting to 1x Dell S4128 (sw1) with a single uplink (vmnic0) for vSAN traffic and 2 uplinks to another switch for VM traffic (vmnic4 and vmnic5)
I have now put in 2x S4128s (sw2 and sw3) in a VLT configuration and created LACP channels to the hosts on vmnic1 and vmnic2 to each switch (sw2 and sw3). The LACP channel is established and working. I have uplinked this VLT 'Stack' to the original sw1 and confirmed traffic is passing across all switches.
My thinking was that I would add the LACP channel as a standby uplink, then one at a time put the hosts into Maintenance Mode, disconnect vmnic0 making the LACP active until all hosts were on the new switches.
When I tried to do this I got the error that this is only supported as an intermediate step. I've researched this and discovered this caveat. Because only one LAG or only standalone uplinks can be active. Now this sounds to me that if one host starts using the LAG, all hosts will start using the LAG which may cause downtime, or make all of the vSAN hosts unreachable from each other.
Please can someone advise me on the best way to achieve what I am trying to do without downtime?
My next option will be to arrange downtime and shut down all VMs and make the change, but I'm hoping to avoid this.
Thanks
Steve