At this time, you should note the following issues when configuring dom0:
ZFS must be prevented from taking too much memory from dom0. Limit the ARC by adding the following line to /etc/system:
set zfs:zfs_arc_max = 0x10000000
Reboot the system.
Limit dom0 to a specific amount of memory by using the Xen dom0_memoption. For example, if you have 4Gb of memory, give dom0 1Gb in /rpool/boot/grub/menu.lst:
... kernel$ /boot/$ISADIR/xen.gz dom0_mem=1024M ...