Six network ports
VMware vSphere 4 servers with six Gigabit network ports are ideal for delivering performance with the software iSCSI initiator. The improvement over four ports is achieved by separating VMotion and FT traffic from iSCSI traffic so that they do not have to share bandwidth. iSCSI, VMotion, and FT will perform better in this environment.
To configure vSphere 4 servers with six Gigabit network ports, use three virtual switches, each comprising two Gigabit ports teamed together, as shown below. If possible, one port from each of the separate Gigabit adapters should be used in each team to prevent some bus or card failures from affecting an entire virtual switch.
The first virtual switch should have:
- A virtual machine network
- A service console (ESX) or management network (ESXi)
- A VMkernel network with VMotion and FT disabled
- A VMkernel network with VMotion and FT enabled
More than six ports
If more than six network ports are available, you can add more ports to the iSCSI virtual switch to increase available bandwidth, or you can use them for any other network services desired.
Enabling the iSCSI software adapter
You will need to enable the vSphere 4 iSCSI software adapter on each ESX or ESXi server. The iSCSI software adapter is managed from each server’s storage adapters list. Here are some guidelines:
- Enable the iSCSI adapter on each ESX or ESXi server.
- Copy or write down the iSCSI qualified name (IQN) that identifies each vSphere 4 server; it will be needed for authentication later on the SAN.
- Reboot the ESX or ESXi server after enabling the iSCSI software adapter if prompted to do so.
SAN connectivity via iSCSI HBAs enables both offloading of the iSCSI processing from the vSphere 4 server and booting of ESX itself from the iSCSI SAN. HBAs do not require licensing or special networking within vSphere 4 servers as they provide a dedicated network connection for iSCSI only. The physical network for HBAs should be a Gigabit network dedicated to the SAN, just as it is for software initiators. As a best practice, use two HBA initiators (a dual port or two single ports), each configured with a path to all iSCSI targets for failover. Configuring multiple HBA initiators to connect to the same target requires authentication for each initiator’s IQN to be configured on the SAN. (See Figure below.) Typically this is configured in the HP P4000 software as two servers (one for each HBA initiator), each with permissions to the same volumes on the SAN.