iSCSI Boot Process
TheCisco UCS Manager iSCSI vNIC and iSCSIboot information created for the service profile is used in
theassociation process to program the mezzanine adapter, located on the blade server. After the adapter is
programmed,the blade server reboots with the latest service profile values. After the power on self-test (POST),
theadapter attempts to initialize using these service profile values. If the adapter can use the values and log
into itsspecified target, the adapter initializes and posts an iSCSI Boot Firmware Table (iBFT) to the host
memoryand a valid bootable LUN to the system BIOS. The iBFT that is posted to the host memory contains
theinitiator and target configuration that is programmed on the primary iSCSI VNIC.
TheiBFT only uses the first iSCSI vNIC and only Target1 for the initiator-to-target initialization. This
scenariois true even if a second target (Target 2) exists for the first iSCSI vNIC.
Note
Thenext step, which is the installation of the operating system (OS), requires an OS that is iBFT capable.
Duringinstallation of the OS, the OS installer scans the host memory for the iBFT table and uses the information
inthe iBFT to discover the boot device and create an iSCSI path to the target LUN. In some OS's a NIC driver
isrequired to complete this path. If this step is successful, the OS installer finds the iSCSI target LUN on
whichto installthe OS.
TheiBFT works at the OS installation software level and might not work with HBA mode (also known
asTCP offload). Whether iBFT works with HBA mode depends on the OS capabilities during installation.
Also,for a server that includes a Cisco UCS M51KR-B Broadcom BCM57711 adapter, the iBFT normally
worksat a maximum transmission unit (MTU) size of 1500, regardless of the MTU jumbo configuration.
Ifthe OS supports HBA mode, you might need to set HBA mode (also known as TCP offload), dual-fabric
support,and jumboMTU sizeafter theiSCSI installation process.
Note
iSCSI Boot Guidelines and Prerequisites
Theseguidelines and prerequisites must be met before configuring iSCSI boot:
• Toset up iSCSI boot from a Windows 2008 server where the second vNIC (failover vNIC) must boot
froman iSCSILUN, consult MicrosoftKnowledge Base Article 976042. Microsoft has a known issue
whereWindows might fail to boot from an iSCSI drive or cause a bugcheck error if the networking
hardwareis changed. To work around this issue, follow the resolution recommended by Microsoft.
• The storage array must be licensed for iSCSI boot and the array side LUN masking must be properly
configured.
• TwoIP addresses must be determined, one for each iSCSI initiator. If possible, the IP addresses should
beon the same subnet as the storage array. The IP addresses are assigned statically or dynamically using
theDynamic Host ConfigurationProtocol (DHCP).
• Youcannot configure boot parameters in the Global boot policy. Instead, after configuring boot
parameters,you need to include the boot policy in the appropriate service profile.
• The operating system (OS) must be iSCSI Boot Firmware Table(iBFT) compatible.
• For Cisco UCS M51KR-B Broadcom BCM57711network adapters:
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iSCSI Boot