I have a stack of 3x Cisco 3750X switches configured in a Stack. I have 3x VMware hosts with only a few VMs runnings. And a Dell PowerVault MD3200i which we are implementing.
I want to optimally configure the 3750X for ISCSI with Jumbo Frames and Flow Control and whatever else is needed. I found this guide for Dell Equallogic Optimization which I'm guessing would work great for the Dell Powervault ISCSI. ftp://mdc-edge.cloud-grid.net/EqualLogic/equalogic/Cisco3750X.pdf
However, I have a few questions on this as I'm a bit rusty on ISCSI and Jumbo frames and haven't done it in a number of years:
1) The 3750X switch seems to only support enabling Jumbo frames switch wide. VMware seems to only support Jumbo up to 9000 Bytes. So that's what I'd use on the 3750X. However, I can't remember what the repercussions are on all of the other devices connected to the switches from routers, other servers, etc. Since they'll still be operating at MTU 1500, that will work just fine right?
I seem to remember that it only didn't work the other way round, if your MTU is set to 9000 but one of the points on the way is 1500, then it wouldn't traverse.
I just want to make sure that by enabling Jumbo frames on these switches (these are the only switches for all the devices) it doesn't take down the network.
2) In the link its got a bunch of QOS commands, I've never worked with QOS so a) don't know what these commands will do switch wide b) will they have negative effect on any other normal devices connected to the switches? Thanks!