Hey @cemalettin,
Even it is supported to share the same VLAN between vSAN Clusters, it always recommended to have one VLAN per vSAN Cluster to provide traffic isolation and avoid any interferences between the vSAN Clusters.
However, sharing the VDS between clusters is not an issue and provides a single administration. However think that if you have an issue with that shared VDS then it will impact all your clusters and if you want to share any additional portgroup and on your new cluster you have a different configuration for the pNICs then you will be doing the change for all the nodes across clusters.
Of course you can still share and avoid this by using different portgroups, but if you need to modify the number of uplinks at VDS level then you will not be able to do it for all.
In most of the design scenarios based on VVD, when there are some different clusters, there is one VDS per cluster to allow the possibility of 1:1 ratio and avoid the SPOF.
