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iSCSI diskless boot, anyone?

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I have scoured the net, and I can't find anyone that's actually doing this! I'm starting to think it's hopeless, but I thought I'd try here just in case. Seems like everything is configured correctly, so I wonder if I’ve got some false assumptions about how it should work. Basically, I want to take a diskless server (R310), configure it for iSCSI boot via a compliant NIC, create a LUN for the OS on the EqualLogic, and then put a Server 2012 installation DVD into the drive, and install on this LUN.

The problem I’m having is I don’t know how it should work, so I’m not sure where the issue is exactly. At this point, I’ve got the NIC configured to see a LUN on the SAN and it actually does try to boot to that LUN. Of course, the LUN is blank at this point. When I boot into the install disc for Hyper-V Server 2012, it doesn’t find any LUNs on the SAN, even after I load the driver. I’m not sure if this is because I’m giving it the wrong driver (I manually extracted the drivers from the cab from this page under Windows 2012) or if it just doesn’t work that way.

Does anyone have any experience doing this?

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Re: iSCSI diskless boot, anyone?

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Yes.  You also need to make sure that flowcontrol is enabled on the switch, and that spanning tree portfast is enabled.  Since spanning tree can cause ports to delay coming back up after a transition.  Which occurs when the device driver loads.   What kind of switches are you using?  Have you enabled Jumbo Frames?  Older versions of Broadcom FW don't support that.  So I would start with it turned off.   If you are trying to run Jumbo Frames, don't use the default VLAN on the switch.  Not all switches support JF on the default VLAN, VLAN1.

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Re: iSCSI diskless boot, anyone?

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This older thread also has some good information about boot from SAN.

en.community.dell.com/.../20224932.aspx

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Re: iSCSI diskless boot, anyone?

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We booted from SAN for years. In order to boot from SAN using iSCSI we needed to have a physical iSCSI HBA in the server that con be configured to create the handshake during boot. We did the same vwith FC HBA's. The NIC's just don't have the firmware capability to establish an iSCSI connection prior to getting instruction from the drivers in the OS.

 

Good  Luck.

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Re: iSCSI diskless boot, anyone?

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Zerobubble,

The nics being used here are Broadcom NICs that have an optionally licensed iSCSI HBA offload capability.  Dell servers come with the license preinstalled.  So with the proper BC/FW and drivers you can do a boot-from-SAN with ESX.

Regards,

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Re: iSCSI diskless boot, anyone?

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I'm guessing you are using Broadcom NICs?.  You have to make sure the boot rom and firmware on the NICs are current.  firmware less than 5.2.7 will never boot from EQL.   Then getting the correct drivers loaded.   Those are the big issues I've seen.

Regards,

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Re: iSCSI diskless boot, anyone?

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Thanks, Don-

So in theory, if I load the right driver during Windows setup, Windows will suddenly see the LUN on the SAN?

-Jake

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Re: iSCSI diskless boot, anyone?

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Yes.  You also need to make sure that flowcontrol is enabled on the switch, and that spanning tree portfast is enabled.  Since spanning tree can cause ports to delay coming back up after a transition.  Which occurs when the device driver loads.   What kind of switches are you using?  Have you enabled Jumbo Frames?  Older versions of Broadcom FW don't support that.  So I would start with it turned off.   If you are trying to run Jumbo Frames, don't use the default VLAN on the switch.  Not all switches support JF on the default VLAN, VLAN1.

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Re: iSCSI diskless boot, anyone?

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This older thread also has some good information about boot from SAN.

en.community.dell.com/.../20224932.aspx

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#IWork4Dell
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Not applicable

Re: iSCSI diskless boot, anyone?

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We booted from SAN for years. In order to boot from SAN using iSCSI we needed to have a physical iSCSI HBA in the server that con be configured to create the handshake during boot. We did the same vwith FC HBA's. The NIC's just don't have the firmware capability to establish an iSCSI connection prior to getting instruction from the drivers in the OS.

 

Good  Luck.

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Re: iSCSI diskless boot, anyone?

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Zerobubble,

The nics being used here are Broadcom NICs that have an optionally licensed iSCSI HBA offload capability.  Dell servers come with the license preinstalled.  So with the proper BC/FW and drivers you can do a boot-from-SAN with ESX.

Regards,

Social Media and Community Professional
#IWork4Dell
Get Support on Twitter - @dellcarespro

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3 Silver

Re: iSCSI diskless boot, anyone?

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Thanks for the help, everyone. Unfortunately, I've run out of time to continue fiddling with this. It's a shame, but it seems like the lesser of two evils to go ahead and just buy a couple of drives for my server, rather than keep banging my head against this obnoxious problem.

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Re: iSCSI diskless boot, anyone?

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Sorry to hear that, but one nice things about local boot, is the system drive I/O doesn't take up any resource from the SAN.    When you have a bunch of nodes, those I/O's do add up.  

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