svMotion of vSAN VM - expected traffic

[andvm]

Hi,

When compute/storage migrating from one vSAN cluster to another what happens exactly.. (Assume FTT=1)?

1. is one copy of the VM components sent via svMotion to the new cluster and replicated to another host in the new cluster?
2. when do the 2x original copies in the original cluster get deleted?
3. Will the above at any stage generate vSAN traffic on the originating Host/cluster or only vMotion traffic?

Am asking the above as I am seeing both vSAN and vMotion traffic when monitoring the originating host uplinks (originally I thought I should expect only vMotion traffic)

Thanks

[daphnissov · Accepted solution]

It is right to see traffic on both vMotion and vSAN networks. Although the storage data flows from source to destination on the vMotion network, all blocks from the source must be read first. This means traffic must traverse the vSAN network to read those blocks. Once the VM is fully created at the destination (based on whatever storage policy), and the final switch-over is complete after transference of the memory contents, it is deleted at the source vSAN cluster.