Hi I am attempting to setup Xen 4.10 with kernel 4.9.86-30 ( virt7-xen-410-testing, virt7-common-testing ) on CentOS7 After installing everything, the machine was unable to boot and hung in dracut stating it could not find its root device. The testsystem I use is a somewhat aged Dell M915 Blade (Quad opteron 61xx), using an MPT SAS controller for it's SAS boot drives. Stock CentOS 7 reports mpt2sas module being used to access the controller. That module is not present in the modules directory of the 4.9.86: 4.9.86-30: # pwd /lib/modules/4.9.86-30.el7.x86_64 # find . -name "*mpt2*" -print # stock 3.10.0-693: # pwd /lib/modules/3.10.0-693.el7.x86_64 # find . -name "*mpt2*" -print ./kernel/drivers/scsi/mpt3sas/mpt2sas.ko.xz The fun part is, that according to the shipped config, it should be there: # grep MPT2 /boot/config-4.9.86-30.el7.x86_64 CONFIG_SCSI_MPT2SAS_MAX_SGE=128 CONFIG_SCSI_MPT2SAS=m Any idea, what happened? I will try myself to build a new kernel from the corresponding source package to check, what went wrong. As a side note: anyone here, who tried that combo? I know, it's somewhat cutting edge, but as I am finally looking into some sort of modern Xen4CentOS setup to replace our aged setup in our infrastructure, i thought i'd rather settle with something as new as possible to avoid running into "not supported anymore soon" issues. Check hypervisor support matrix on frontpage https://xenproject.org/ Regards Thomas Weyergraf