Re: UCS C240 Windows Boot from iSCSI

allen.george · ‎11-07-2022

We are attempting to boot 3 UCS C240 M4SX servers from iSCSI volumes on Windows 2022. We have the iSCSI connectivity configured on the vNIC and can see the volumes in BIOS. When we load into Windows Setup, we install the network drivers and the NICs connect. The volumes are not showing up in the Windows Setup, and we've made sure to remove the driver disk and put the Windows DVD ISO back into the virtual drive. We've waited for 15+ minutes and rescanned many times. The volume is not being displayed in diskpart either.

The volumes are hosted on Nimble CS700 and we know this process works for VMware (we had 24 blades booting from this storage array). We just can't get the volumes to show up in Windows setup. Is there something we are missing here? We found one article suggesting that you cannot have too many devices listed as bootable in BIOS as it can cause this. Any other thoughts? We need to get this working as the servers do not have raid cards and they need to have Windows installed on them.

Kirk J · ‎11-08-2022

Used to be an issue with the block size (i.e. Pure storage only supports 4MB SCSI commands but Microsoft Windows sends 8MB SCSI commands during UEFI boot from SAN operations).

Can you try using legacy boot (or are you already using legacy) ?

Also if you are trying to use jumbo frames, I would turn that off until connectivity issues are resolved.

Also recalling when Windows install couldn't handle multiple paths to same LUN (had to disable all but one untill after install completed). Not sure if that limitation still exists.

Kirk...

allen.george · ‎11-08-2022

Hi Kirk,

Thanks for replying. We have it booting in legacy and we do have jumbo frames (they work with ESXi) but they are not configured on the networking on the servers right now.

We have the vNIC driver installed in the Windows installation and it is getting an IP and can ping the storage on the iSCSI network, but it is not auto-mounting the iSCSI volume. Is there something we have to do to trigger that?

Adding some more information. We see the volume attached in BIOS boot when we switch to UEFI boot, it shows the volume and correct size on the boot screen. I cannot see a way to make the volume show up in the boot list in the BIOS though. The server shows connected to the storage after it starts booting, but disconnects once the Windows Installer boots off the disk. We've tried legacy boot and UEFI as it seems legacy is not supported on Server 2022. Loading the driver for the VIC 1227 in the Windows installation does add the interfaces and the one that is configured in the iSCSI VLAN does DHCP in the proper range.

I put the server back to legacy boot configuration and loaded back in and it stayed connected to the storage array even after the drivers were installed. However, Windows does not see the storage. We are likely going to abandon this if we can't get it working pretty soon.