should I stack switches

One benefit of trunking though is the ability to do firmware upgrades 1 switch at a time. With a stack, you will need 100% downtime on the whole iSCSI environment when you do a switch firmware upgrade.

You can upgrade your Equallogic firmware without downtime (if you set up your environment properly (specifically the hosts), you can update your hosts 1 host at a time and assuming you run a cluster of some sort, this also doesn't mean downtime for your end users... but a switch stack would require 100% downtime if you want to upgrade the firmware.

Thanks for both of your answers.

"Stacking is better than trunking.  Less overhead, lower latency, higher throughput"

Can you expand on "less overhead" as I'm not sure what you mean on this?

I've been searching but I can't find a clear recommendation from dell on whether to using stacking cables or not.

Thanks again,

H

Re: Overhead.  When you bond, the switch CPU has more work to do, dealing with spanning tree and moving traffic across the various ports.  The load goes up the more ports you trunk..

Will there be any issue if our iSCSI switches are neither stack nor trunk? But just two isolated switches for HA?

When rebooting EQL for firmware update or switching of ports, I do notice that passive ports on EQL could become active to take over a previously active ports. Could this resulted in one iSCSI switch having 75% or even 100% of the active iSCSI paths while the other switch has only 25% or none at all?

Hello,

 No, that will not work.  For EQL SANs the switches must either be stacked or trunked together.  The array will use any available port to reach any server port. 

 Regards,

don