User guide

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High Availability: A typical data center is highly redundant in nature - redundant paths, redundant disks and

redundant storage controllers. When operating system images are stored on disks in the SAN, it supports

high availability and eliminates the potential for mechanical failure of a local disk.

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Rapid Redeployment: Businesses that experience temporary high production workloads can take

advantage of SAN technologies to clone the boot image and distribute the image to multiple servers for

rapid deployment. Such servers may only need to be in production for hours or days and can be readily

removed when the production need has been met. Highly efficient deployment of boot images makes

temporary server usage a cost effective endeavor.

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Centralized Image Management: When operating system images are stored on networked disks, all

upgrades and fixes can be managed at a centralized location. Changes made to disks in a storage array

are readily accessible by each server.

5.5.2 Configuring Boot From SAN on the Cisco Unified Computing System

With boot from SAN, the image resides on the SAN and the server communicates with the SAN through a host

bus adapter (HBA). The HBAs BIOS contain the instructions that enable the server to find the boot disk. All

Fibre Channel capable CNA cards supported on Cisco UCS B-Series Blade Servers support Boot from SAN.

After power on self test (POST), the server hardware component fetches the boot device that is designated as

the boot device in the hardware BOIS settings. Once the hardware detects the boot device, it follows the regular

boot process.

Note: The 2 SAN fabrics are disjoint from data perspective and with the dual port HBA‘s and storage controller redundancy is

provided.

There are three distinct portions of the BFS procedure:

1. Storage array configuration

2. SAN zone configuration

3. Cisco UCS configuration of service profile

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Storage Array configuration: First, the storage array admin has to provision LUNs of the required size for

installing the OS and to enable the boot from SAN. The boot from SAN LUN is usually LUN 0. The SAN

admin also need to know the port world-wide name of the adapter so that the necessary lun masking is put

in place. The lun masking is also a critical step in the SAN LUN configuration.

For example, in case of NetApp 3140/3170 storage array, the storage admin has to create a BootVolume

and then include the blade WWPNs into a initiator group and add them to the port WWPNs where the

storage is configured as shown below.

Task description

Create a separate boot from SAN Aggregate

Create a Volume on top of that, call it BootVolumes

Add LUN on the BootVolumes, let‘s call it BFS-Server-9 and 50 GB of space