NetApp and VMware vSphere Storage Best Practices

The default block size of a virtual machine file system is 1MB. This block size supports storing virtual disk
files up to a maximum of 256GB in size. If you plan to store virtual disks larger than 256GB in the datastore,
you must increase the block size to be greater than the default (see Figure 9).
Figure 9) Formatting a LUN with VMFS.
4.5 CONNECTING ISCSI DATASTORES
As a best practice NetApp recommends separating IP-based storage traffic from public IP network traffic by
implementing separate physical network segments or VLAN segments. This design follows the architecture
of SCSI and FC connectivity. New with ESX and ESX 4.0 is the ability to enable multiple TCP sessions with
iSCSI datastores. Enabling multiple TCP sessions with the ESX Round Robin PSP will allow iSCSI
datastores to send I/O over every available path to an iSCSI target.
For more information on configuring NMP for iSCSI, see 5.4 Configuring the Round Robin PSP
To create a second network in ESX requires one to create a second vSwitch in order to separate the traffic
on to other physical NICs. The ESX Server will require a VMkernel port to be defined on the new vSwitch.
Each ESX Server should have a service console port defined on the vSwitch that transmits public virtual
machine traffic and on the vSwitch configured for IP storage traffic. This second service console port adds
the redundancy in ESX HA architectures and follows ESX HA best practices.
With this design it is recommended to not allow routing of data between these networks. In other word, do
not define a default gateway for the iSCSI storage network. With this model iSCSI deployments will require a
second service console port be defined on the VMkernel storage virtual switch within each ESX server.
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