From: "Frank Haber" 

Since I've just played with this (with SBS4/4.5, which is NT4).....

The NT boot partition must be entirely within the first 8GB.  It doesn't
have to be the first.  But the BIOS must inherently support 8GB partitions,
if you don't want trouble later.  With no SPs, the boot volume should be
>4MB. All this varies wildly for SCSI and RAID, depending on SP and
whether your SCSI setup needs a floppy or not.  SCSI boots first, unless
you have a late SP and/or a magic machine BIOS.

If the install files are truly SP6a (slipstreaming didn't happen until
later, so the creation process was extremely laborious for anyone but an
OEM), you can have 8GB system and big secondary/extended partitions. 
Possibly only SP4 is required for this.

There were subtle changes to NTFS over the service packs, so get up there
as fast as possible with your patching, and fercryingoutloud don't try to
defrag with old utils or other suicidal stuff.  I don't believe you got a
defrag with NT4; in any case, everyone used Diskkeeper.  V5 or above should
be fine.  Any Perfect Disk likewise.

Everyone likewise used third-party backup.  Stick with simple-video
programs. Luckily, your virtualized drivers will likely be better than half
the ones people had to use, back in the day.

Make sure you have boot floppies that work.  Make sure the floppy drive
boots DOS.  If you have RAID, make two copies of the RAID install floppy. 
And remember - YOU HAVE NO USB!!  Don't depend on thumb drives.  Get the
network working smoothly, pronto, or plan on burning a lot of temp CDs. 
I'd recommend NETBEUI on source and destination for real smoothness, but
the virtual supervisor probably doesn't support that.  Stick with ONE,
common, vanilla, known-good NIC.

--- BBBS/NT v4.01 Flag-5