Data Backup and Recovery

iSCSI Boot on FAS3070?


I'm looking for info about how to do diskless Windows boot from a FAS3070 with GbE iSCSI. Would appreciate any tips and pointers. Thanks,   -Wei



If you want a software only solution, take a look at gPXE pages:

Works pretty well when you figured out how to make it work... Not a very "user friendly" system, but still, very effectIve.

And when you HAVE IT WORKING it, you have learnt a lot of things !




I am somewhat skeptical about the content of that page.

E.g. this:

to my eyes looks like assuming that simly transferring a boot image to an iSCSI target does the trick of iSCSI boot (last step says "iSCSI support is built in to Server 2008. If you are booting from iSCSI, you can immediately transfer the Windows Server 2008 disk image to your iSCSI target.")

Or am I missing something?

Or do they simply use gPXE (running, say, off USB stick) as a boot loader, which in turn loads the actual OS?



It's a 2 stages boot phase (like always).


gPXE acts like a BIOS extension: it provides int13h redirection to iSCSI target.

It makes the OS able to load "enough" (kernel, boot drivers...).


Then, you need the "disk drive driver" to continue booting. In this case, you need the iSCSI "initiator".

There are several free iSCSI initiators for Windows. microsoft has one which is in Win2008 server by default. For other OSes I think you need to install it.

There is also StarPort iSCSI initiator:

When the initiator (the "disk drive driver") initalizes, it provides "disk access" (a disk drive is seen by the OS, said disk drive being a remote iSCSI target) for the OS to continue booting (the OS does not uses int13h anymore then and gPXE can theoretically be unloaded)

Note that gPXE can be loaded from various kinds of storage, including PXE boot program, floppy boot (or floppy emulation), Boot-ROM...

I have read that some versions of Linux KVM (Kernel Virtual Machine) use gPXE as their "PXE ROM".

In order to boot WIndows from iSCSI, I think you have some other explanations here:

Booting Linux off iSCSI using software only is also possible...



Just a quick update; I've successfully performed iSCSI boot of an IBM x3850 X5 server from a NetApp FAS3070. The OS is Windows 2008 R2, so the iSCSI initiator comes with it. The NIC is onboard Broadcom. The server was boot ROM enabled but I didn't need to use gPXE.

Thanks to the tips and discussions on this thread. Especially to Olaf, Andrey, Mrlevivigatt.





you did this without an HBA and just the Broadcom NIC card?




The answer is yes! One of the major reasons we tried that was to do it HBAless; that way, we can save slots inside the server for other purposes.




Congratulations Tom,

Just one suggestion here. In my testing it is important to tweak some reg settings, especially to survive initiated or unplanned failover..

HKLM\SYSTEM\CurrentControlSet\Services\Disk\TimeOutValue: <190 or lower depending on the size of your environment>

This is the time in units of seconds before an SRB request initiated by the disk class driverwill time out.

HKLM\SYSTEM\CurrentControlSet\Control\Class\{4D36E97B-E325-11CE-BFC1-08002BE10318}\<InstanceNumber>\Parameters\MaxRequestHoldTime: <180 or lower again depending>

This is themaximum time (seconds) for which requests will be queued if connection to thetarget is lost and the connection is being retried. After this hold period,requests will be failed with "error no device" and device (disk) willbe removed from the system.

This will make your clients more robust.




Hi Wei,

In all opportunities I was involved so far a couple of internal drives for boot image proved to be simpler & actually cheaper solution than a couple of boot-from-SAN-enabled iSCSI HBAs.




Hi Radek,

Thanks for sharing your experiences. I'm doing this as a lab test, not real world deployment. I'm trying to see if the diskless iSCSI boot is doable. If so, how?




Your server vendor would be in the best position to provide information about iSCSI boot. This depends on BIOS support, versions of Broadcom firmware, supported drivers etc.

It is definitely working. Where it becomes interesting, when you need move the whole server to different system. There are solutions that offer automatic failover in case of server failure (including making proper LUN masking adjustments etc). The nice thing is, no changes are required in operating system or application, no cluster software.

Windows 2003 cannot be installed directly on iSCSI initiator; you need to install it on local disk, copy onto iSCSI LUN and make adjustments so that system boots. Some vendor installation tools automate it. Windows 2008 can be installed directly on iSCSI LUN; again it is best to ask server vendor about required driver versions, BIOS support etc.


Ha,  server vendor is counting on me to get it to work. Thanks,  -Wei


Here is a couple of links that describe how to configure NIC part; Dell even describes manual steps needed to convert disk-based w2k3 install to iSCSI-based one. HTH


With best regards

Andrey Borzenkov

Senior system engineer

Service operations


Honestly? I've never seen it working. Not because it refused to work, but simply no one around me was keen enough to actually test / implement this

Having said that, you may google it & actually it turns out some people made it working, e.g.:

(iSCSI HBAs involved though)




For the broadcom stuff you'll need the Microsoft iSCSI Boot Initiator Software (2.0.8).

Not sure how that works for Windows 2008, though, since iSCSI is built-in.

Check out the installation instructions for that boot initiator.

Setting up the Boot LUN may be the toughest bit

Like prepping it from a different machine through the software initiator.




The IMT (Interoperability Matrix Tool) on lists some iSCSI HBA's that are officially supported.

The HBA needs to have a bootable BIOS extension.

For Management you may still need to install the Microsoft iSCSI  Service from the s/w Initiator package.

Note that, when using Snapdrive you can't take Snapshots of the boot disk, and

you absolutely need to put in the IP Address of the Filer that is reachable from

a normal network interface, since you can't use the iSCSI HBA for normal network traffic,

since to the system it looks like a SCSI adapter (afaik).

There are also MB chipsets that can use the iSCSI Boot Initiator from Microsoft.

If you already have an Bootable iSCSI HBA, you need to go into the BIOS to setup the Filer's

IP Address as a target. Make sure you have a windows or windows_gpt style LUN mapped to 0

to an igroup with the iSCSI HBA's initiator iqn and you can install the operating system

from a CD/DVD, after a reboot.




Hi O,

Thank you for the tips. I don't have an iSCSI HBA. I have a NIC (Broadcom) which is boot ROM enabled. Do you have step by step guide that I can follow?



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