There are many topics on boot from SAN and auto deploy. For us, boot from SAN made more since because we have an exisiting fiber network in place. We do not however have all of the components needed for auto deploy (DHCP, TFPT, ect). In this boot from SAN environment, I am working with a few Dell M1000e chassis, M710HD / M610 blades, dual QLogic QME 2572 cards, dual intel 10GB cards, Cisco 3130XS, Broacde fiber switches and an EMC SAN.
I am not going to cover provisioning a LUN or zoning because they can be different on whatever vendor you use.
The first thing you want to do is decide on is a flex address. Will you want the boot LUN to follow the blade or stay assigned to the WWN of the chassis slot? We liked the idea of being able to plug in a spare or replacement blade into the slot in order to bring systems back online quickly.
Reboot the server and hit “ctrl-q” to enter the qlogic Fast!Util.
This will give you a selection of the adpater addresses.
In the menu for the adapter, be sure to enable “host adapter BIOS”. This is disabled by default.
If you have provisioned and zoned your luns already, you will see the selecable boot luns. Be sure to set the correct order for these. Typically you would have these go across storage processor A or B. Be sure to create an even load in your environment in case all the hosts reboot.
The next task is to configure the BIOS.
In the “hard disk drive sequence”, set the daughter card as the first boot device.
Make sure to set the correct boot order.
When the system reboots, you should see the LUN you are booting to.
When you go to install the host, you will see the option to install on LUN you have provisioned. If you see an incorrect volume size here, go back to your QLogic configuration and make sure you have selected the correct LUN to boot from.
I recommend to only provision the LUN needed for the install when going through the initial setup.
Why are companies still using boot from SAN? What’s the difference from Auto Deply?
1. You can replicate the SAN to a DR site and have hosts on standby. This can be achieved also with auto deploy, if you replicate all components to the DR site.
2. The SAN can take snapshots of the LUN, which enables a roll back in case something happens to the host install. Auto Deploy is a stateless boot option, you have to use image builder and rely on host profiles to keep everything synced. You would still want to use host profiles even with boot from SAN.
3. Servers can be diskless with boot from SAN. This is the same for Auto Deploy, the hypervisor is actually loaded into RAM.
4. A master image can be used with boot from SAN by cloning the lun for other hosts. There are still steps involved to zone the LUN properly. Auto Deploy is similar, you still need to assign the MAC to the image you want to boot from.
This is not really a comparison between boot from SAN and auto deploy, I just wanted to show the steps for setting up boot from SAN from Dell.