M4300 stack vs non stack, VMware and iSCSI setup

Hi

You "sort of" can upgrade the firmware independently within a M4300 stack as LaurentMa discussed in this thread here: Reboot all stack members, then the standby master, and finally the old master. However I have come to realize that during such an update you will have a temporary firmware code mismatch until you have rebooted the stack master AND all the ports of the rebooted stack member remain down until you reboot the stack master. When the old master reboots, a new stack master quickly gets elected and the ports of the new stack master and the other (rebooted) stack members ever so quickly change to UP status. (During a code mismatch I could not initiate a failover of the stack master to a backup standby switch.)

I have to say that I was also surprised to learn that many other stackable switches from other vendors don't support staged updates of stack members but only certain product lines that are usually in an even higher price segment or focus on datacenter switching.

TL;DR: Since you use iSCSI where I/O timeouts can lead to host or VM crashes I'd rather consider the second option. For the iSCSI part, consider making 2 VLANs and 2 Subnets where 1 subnet/VLAN is only on first switch and the other on the second switch. Then you can configure multipathing on the VMware side. With Linux and Windows you can often configure round-robin mode where both connections are used in active-active mode. However I suggest you read up on how to properly do this by reading both Synology and VMware manuals on that topic and figure out a way how to get this configured properly. I'd discourage combining LACP and Multipathing together.