If you plan to set up and use an iSCSI LUN as the boot device for your host, you need to follow certain general guidelines.

These guidelines apply to booting from software and dependent iSCSI, and independent hardware iSCSI.

Review any vendor recommendations for the hardware you use in your boot configuration.

For installation prerequisites and requirements, review an appropriate ESX/ESXi Installation Guide.

Use static IP addresses to reduce the chances of DHCP conflicts.

Use different LUNs for VMFS datastores and boot partitions.

Configure proper ACLs on your storage system.

The boot LUN should be visible only to the host that uses the LUN. No other host on the SAN should be permitted to see that boot LUN.

If a LUN is used for a VMFS datastore, it can be shared by multiple hosts. ACLs on the storage systems can allow you to do this.

Configure a diagnostic partition.

With independent hardware iSCSI only, you can place the diagnostic partition on the boot LUN. If you configure the diagnostic partition in the boot LUN, this LUN cannot be shared across multiple hosts. If a separate LUN is used for the diagnostic partition, it can be shared by multiple hosts.

If you boot an ESXi host from SAN using iBFT, you cannot set up a diagnostic partition on a SAN LUN. Instead, you use the vSphere Management Assistant (vMA) to collect diagnostic information from your host and store it for analysis.

See Collecting Diagnostic Information for ESXi Hosts.