Debian wheeze PV guest example:

virt-install \
--debug \
--paravirt \
--name=deb \
--network bridge \
--disk path=/dev/zvol/dsk/rpool/xen/deb,driver=phy \
--location=http://ftp.nluug.nl/pub/os/Linux/distr/debian/dists/wheezy/main/installer-amd64/ \
--nographics \
--ram=480

INFO for CentOS guest:

For VNC install you need provide about 800MB RAM. For text mode you can use 512MB

CentOS 6.x 64 bit PV guest example:

virt-install \
--debug \
--paravirt \
--name=cos \
--network bridge \
--disk path=/dev/zvol/dsk/rpool/xen/cos,driver=phy \
--location=http://ftp.nluug.nl/pub/os/Linux/distr/CentOS/6.8/os/x86_64/ \
--nographics \
--ram=800

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