Is UEFI required for ZFS?

[Thomas Laus]

I have a new Asus H170-Plus-D3 motherboard that will be used for a DOM0 Xen 
Server.  It uses an Intel i5-6300 processor and a Samsung 840 EVO SSD.  I 
would like to use ZFS on this new installation.  The Xen Kernel does not have 
UEFI support at this time, so I installed FreeBSD CURRENT r295345 in 'legacy 
mode'.  It takes about 7 minutes to go from the first '|' character to 
getting the 'beastie' menu.  I changed the BIOS to UEFI and did another 
installation.  The boot process goes in an instant.  Thinking that it may be 
an issue with FreeBSD CURRENT, I installed FreeBSD 10.3 BETA 1 in both legacy 
and UEFI mode.  The results were the same.  BIOS Legacy mode with a default 
ZFS installation takes nearly 7 minutes to get the Beastie menu.  An UEFI 
installation with ZFS is instantanious.  A default GPT installation of both 
CURRENT and FreeBSD 10.3 BETA1, either legacy or UEFI, also gives an instant 
bootup.

How can I dig deeper into my problem?  I would like to use ZFS with my Xen 
Server.

Tom

-- 
Public Keys:
PGP KeyID = 0x5F22FDC1
GnuPG KeyID = 0x620836CF