Boot from SAN Policy for Multiple Severs

gaskincharles · ‎05-04-2011

I have a question in regards on what to do when you are trying to use one SAN boot Policy which is attached to a Service Profile Template for multiple server.

My issue is that I have setup my service profiles to point to one SAN Boot Policy, and in that policy I have specified the LUN ID for my SAN primary and secondary targets. But what happens when with the 3rd or 4th server since the LUN I created for them has not been specified in the boot order ? Is there some type of generic LUN ID I am supposed to assign the primary and secondary targets ?

David.Jarzynka · ‎05-04-2011

On a Boot-from-SAN policy the LUN ID for boot is usually 0 or 1, but really can be anything in the policy. This policy is designed to aid to server is booting from many different storage controllers, if one should fail, another path will and should be used at boot. This policy is not designed to act a LUN mask, that is the job of a SAN fabric switch.

I can only assume that you are zoning on the SAN fabric with an MDS or Brocade fiber switch. If so, this will provide separation for all servers at boot via zoning. All servers will be booting to different LUNS, but all will be using the LUN ID of 0 or 1. Since they will be separated via zones, this will keep you booting just fine.

From a SAN fabric prospective each server will have its own boot LUN (ID 0 ro 1), and zone within the fabric. This a common best practice.

gaskincharles · ‎05-04-2011

David thank you for your response. I am using a Cisco 9124 MDS switch. Are you saying that the redirection to the proper LUN on the storage device is handled through just the switch, and that as long as the one to one zoning is setup between the UCS HBA's and my my Storage HBA's the switch will know where to redirect the request upon boot ?

jason.lempka · ‎05-04-2011

In our environment, the zoning on the switch (Nexus 5548s for us) determines which initiator can talk to which target SAN. The lun masking on the SAN determines which lun is presented to which initiatior. The zoning allows for all UCS blades to talk to our SAN. The lun masking allows the SAN to present LUN A to UCS01 only and LUN B to USC02 only, etc.

You need two pieces of configuration, one on your MDS and one your SAN.

David.Jarzynka · ‎05-05-2011

Yes, if you have boots LUNs created for each UCS blade on the SAN and the WWPN for each blade HBA is zoned correctly in the MDS, the blades will boot properly.