3 Replies Latest reply on Dec 9, 2019 4:07 PM by KabirAli82

    Reconfigure VSAN/VMotion VLAN and MTU setting on production system.

    djblue Lurker

      Hello I have a 3 host VSAN HA Cluster setup which I originally configured as a lab but has since grown into hosting some production VM's.  No VLan's were configured in the original setup but we have now installed some Cisco 3850's and I would like to assign the VSAN and vMotion ports groups to separate VLANs and increase MTU setting to support Jumbo frames to increase the overall performance of the cluster.   Is this a pretty straight forward process?  Can i just go ahead and change the port group VLAN ID and MTU settings on the live system? is there anything I should do to the system prior to making this change such as turning off the virtual machines.  I don't really want to turn off the VSAN or HA setup if I can avoid it.

       

      Any tips would be great.

       

      Cheers

        • 1. Re: Reconfigure VSAN/VMotion VLAN and MTU setting on production system.
          KabirAli82 Enthusiast

          How is the network setup? Before you begin make sure to create a backup of you current DVS settings.

          If you have 2 uplinks this can be done with some testing and without production impact. Simply create a new DVS/port group with the correct VLAN. Assign one uplink to the new DVS/port group. Test if the setup is still working. Change the MTU size and retest is everything is working. Finally add the other uplink to the new DVS/port group.

           

          If you have one uplink. I would shutdown the VM's before starting. First try the new VLAN, if it works change the MTU size.

          • 2. Re: Reconfigure VSAN/VMotion VLAN and MTU setting on production system.
            djblue Lurker

            Hi thanks for responding.  Here is an overview of my setup:

             

            I have 4 Nic's

             

            vmnic0 (Uplink4) = 10GB - Port group Vmotion and VSan

            vmnic1 (Uplink3) = 10GB - Port group Vmotion and VSan

            vmnic2 (Uplink2) = 1GB - Virtual Machines/ Management

            vmnic3 (Uplink1) = 1GB - Virtual Machines/ Management

             

            Im guessing that according to your response I would do the following:

             

            **Backup config first.

            1).  Unassign one of the uplinks from the Vmotion/VSan port groups

            2). Create new dswitches for vmotion and vsan with the new vlan setup

            3). Assign the free uplinks to the new dswitches.

            4). Test connectivity.

            5). Repeat for the next uplink.

             

            Anything I'm missing?

             

            Thanks a lot.

            • 3. Re: Reconfigure VSAN/VMotion VLAN and MTU setting on production system.
              KabirAli82 Enthusiast

              I dont have access to an ESXi host so the order could be off a little. But this is what I would do:

               

              1) Create a backup of the current DVS

              2) Optional: create a new DVS with MTU 1500 (in this example called Prod-DVS)

              3) Create a new port group for vMotion with the correct VLAN (in this example called PG-Prod-DVS-vMotion-VLAN XX)

              4) Create a new port group for vSAN with the correct VLAN (in this example called PG-Prod-DVS-vSAN-VLAN XX)

              5) Edit the new port groups and set uplink1 = active and uplink2 = standby

              6) On host 1 (ESXi-01) create a temporary vmkernel adapter for vMotion in the same IP range as the current vMotion network (in this example i assume its vmk3)

              7) On host 1 (ESXi-01) create a temporary vmkernel adapter for vSAN in the same IP range as the current vSAN network (in this example i assume its vmk4)

              8) Repeat steps 6 & 7 on host 2 (ESXi-02)

              9) Assign vmk3 and vmk4 to the new port groups (PG-Prod-DVS-vMotion-VLAN XX & PG-Prod-DVS-vSAN-VLAN XX)

              10) Enable SSH on ESXi-01 and fire up SSH

              11) vmkping -I vmk3 x.x.x.x (replace x.x.x.x with IP of the temporary vMotion vmkernel IP of ESXi-02)

              12) vmkping -I vmk4 x.x.x.x (replace x.x.x.x with IP of the temporary vSAN vmkernel IP of ESXi-02)

              13) Ping ok? Then next step, else troubleshoot

              14) Edit PG-Prod-DVS-vMotion-VLAN XX & PG-Prod-DVS-vSAN-VLAN XX and change uplink1 from active to standby and uplink2 from standby to active

              15) Repeat steps 11 & 12

              16) Ping ok? Then next step, else troubleshoot

              17) Edit PG-Prod-DVS-vMotion-VLAN XX & PG-Prod-DVS-vSAN-VLAN XX and set both uplinks as active (or which setup you want to use)

              18) Change MTU size of Prod-DVS (step 2)

              19) Change MTU size of vmk3 & vmk4 on ESXi-01 & ESXi-02

              20) vmkping -d -s 8972 x.x.x.x (replace x.x.x.x with IP of the temporary vmkernel IP of ESXi-02)

              21) Ping ok? Assign the "old" vMotion and vSAN vmkernel adapters to the new port groups and change the MTU size of both vmkernel adapters.

               

              This should do the trick!