Hello all,
Have been experimenting recently with XenServer 6.2 and FreeBSD 10.1 amd64 trying to get it work in different modes (particularly PV, PVHVM, HVM) and here what I got:
Vadim.
Have been experimenting recently with XenServer 6.2 and FreeBSD 10.1 amd64 trying to get it work in different modes (particularly PV, PVHVM, HVM) and here what I got:
- Default installation on UFS went without errors, but performance is very poor.
ioping
shows low numbers ~ 1k IOPS. Can't get UFS fast though some articles say UFS should be faster under virtualization environment than ZFS. - The same installation on ZFS shows great number of IOPS and server is fast indeed. I got 100k IOPS for the same setup. The only problem during installation: kernel panic due to the lack of swap space. Have this error on 2GB RAM and don't have on 6GB.
- Latest FreeBSD releases already contain Xen PVHVM support at kernel, but in fact you can't use extra functions until you install Xen guest tools. Particularly - can't shutdown, restart, suspend VM from the host. The only option - hard reset, killing domId.
- After installing guest tools got control over VM through
xe vm-*
commands. VM status shows it is still running at HVM mode.
- PV mode is only available for i386 kernels. All examples for PV settings are done for Xen hypervisor only and for older releases 6.0, 7.0 -- 9.0. There is no PV support for XenServer guest. It seems PV support for newer kernels is not under development anymore. Is that right?
- Classically it states that PV mode should give more performance than HVM. Some articles claim that PVHVM under FreeBSD is faster than PV. So I guess BSD development goes for this specific PVHVM implementation. Other OS support either PV or HVM, but PVHVM seems to be something "unnatural" and invented by FreeBSD team. Is this right?
- Still missing text console from the host. It seems that PVHVM mode really performs well (from the point of IO ) but is not recognized by hypervisor and does not give functionality that PV guests suppose to have. Is that right?
- What are the plans for development in this area? Will it be PV for amd64 in the nearest future? Or something better?
Vadim.