02-11-2010 04:03 AM
This is an unmanned remote site and so we want the ability to 'replace' a failed server by moving its profile to another bay where there is a spare blade.
We also want to get that spare server to boot from the same OS LUN on the MSA, so that it becomes the failed SQL Server, IIS box, or whatever, and hopefully carries on where the other left off.
So the problem is - how can the spare server take on the host name (IQN?) of the failed one, coutesy of VC, so that it picks up the same volume presentation?
Any suggestions or guidance gratefully accepted!
02-11-2010 05:25 PM
The VC profile does two things.
1. It virtualizes the MAC addresses on the server NICs. and
2. It virtualizes the HBA WWN.
I dont know which OS('s) you are running, (and my comments may be completely off the mark), however the "VC Profile" approach is based on the assumption that you are going to boot from some source which is external to the blade, i.e. from a SAN volume.
Storage presentation is based on WWN, (i.e. storage is presented to the Virtual WWN assigned to a server HBA, in the VC Profile). I would assume that the system hostname is associated with the boot volume, not the blade, and any blade which boots from a given boot volume would assume the hostname incorporated into that boot pack.
Considering only the HBA's and WWN's. When a profile is applied to a blade, and the blade is powered up, the "real" WWN on the HBA's are overwritten by the virtual WWN's from the profile. Any storage which was presented to the (virtual) WWN's will now be available to the server. If one of those presented LUNs is your boot disk, then you should be able to boot from it.
Note: What I am describing here is how it works with my OS (OpenVMS). However in my enclosures I am also running Windows and Linux, and neither of my other administators have expressed any concerns about being able to flip between blades using the profiles, so I must assume that it is doable.
02-12-2010 12:42 AM
We will be running Win Server 2008 R2. The issue here is that the OS images to boot from will be on an iSCSI SAN, not FC, so the WWN (which VC seems to support well) does not apply.
In a training lab recently we set up a MSA2000i to present a volume to the blade, but it relied on the blade's iSCSI name (IQN.whatever) to make the connection. In our exercise, this was derived from the MS iSCSI initiator, but in a pre-boot environment, this has to come from the BIOS. All well and good if you are tying a fixed server to a volume, but what we want to achieve is hardware virtualisation - the ability for a standby server to take on the identity of a failed unit, and so boot from its OS volume.
So, as far as I can see, we must somehow cause the IQN generated by the BIOS to be varied by the VC profile.
I had hoped this could be done by basing it on the adapter MAC address, which VC does of course support.
But that's where I've got stuck.