Greetings, I found your post here and was very pleased with what I read. Your experience seems to blessed you with a good amount of knowledge in this area. Here is my set up with 3 Hosts. Recently we started experiencing some iSCSI network latency issues (above 20ns) between the VM's would you be so kind to give me some recommendations based on our environment? Below is our inventory of equipment, and its current basic configuration. We are / have recently added a couple new stacked switches (layer 3) and have moved the VMotion network onto its own VLAN and are working tword doing the same for the MGMT lan. (We have one of the hosts already on its own VLAN/Network).
3 ESXI hosts (2xDell R620,1xDell R720) each with 3x4 port NICS (12 ports total), 64GB RAM. (Wish I would have put more on them ;-))
1 Dell MD3200i iSCSI disk array with 12 x 450GB SAS 15K Drives (11+1 Spare) w/2 4 port GB Ethernet Ports
2 x Dell 5424 switches dedicated for traffic between the MD3200i and the 3 Hosts
Each host is connected to the iSCSI network though 4 dedicated NIC Ports across two different cards
Each Host has 1 dedicated VMotion Nic Port connected to its own VLAN connected to a stacked N3048 Dell Layer 3 switch
Each Host will have 2 dedicated (active\standby) Nic ports (2 different NIC Cards) for management
Each Hosts will have a dedicated NIC for backup traffic (Has its own Layer 3 dedicated network/switch)
Each host will use the remaining 4 Nic Ports (two different NIC cards) for the production/VM traffic)
Currently those remaining 4 VM nics are connected to our current production switch (NO VLANS) so we have a lot of broadcast traffic with about 150 devices connected. We will/are working tword creating separate VLAN's and segmenting our network out. Hard to do while the environment is in production. So we are carefully planning.
Also are there other option to gaining some performance out of our iSCSI environment that may not be obvious to us. When I built this system 4 years ago, I tried to plan ahead, asking questions and making sure I had plenty of redundancy and bandwidth, now I am finding out maybe not the case, as when snapshots are being created for the backups (Unitrends client) more often than not latency issues are causing orphaned vmdks that we have to delete later. (Consuming disk space)
If there is any further information you need, or screenshots of our network config on the hosts I would be glad to share them with you.
Thank you in advanced!