I don't know much about virtualization, but could anyone explain how sites such as [1] and [2] are able to virtualize OpenBSD? Do you think they develop the Xen support internally?
FreeBSD on EC2 FAQ
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Re: FreeBSD on EC2 FAQ
#12I don't know much about virtualization, but could anyone explain how sites such as [1] and [2] are able to virtualize OpenBSD? Do you think they develop the Xen support internally? [1] http://bsdvm.com/ [2] http://www.rootbsd.net/blog/2010/openbsd-4-8/
Short answer: There's two types of virtualization.
With full virtualization, you can run unmodified operating systems (in theory, at least). VMWare is an example of a fully virtualized system. Recently Intel and AMD added features to their CPUs which make this much easier.
With para virtualization, the guest operating system is aware of the hypervisor and cooperates with it -- for example, rather than modifying page tables directly, it sends a message to the hypervisor saying "please map this page for me".
(There's also a hybrid 75%-virtualized model, where the system is fully virtualized except that some devices are exposed via hypervisor calls -- this is seen most commonly as Xen "HVM with PV drivers".)
Re: FreeBSD on EC2 FAQ
#13Earlier quoted context omitted.
Hardware support has always lagged Linux (and still does). Not everywhere. Last I checked we do considerably better for 10GbE, for instance. We certainly consistently lag behind Linux for desktop hardware support, but I think we hold our own pretty well in the server space. As a BSD hacker who hates anything hardware-related, however, I do love the idea of outsourcing such irritants, though.
I held this view ("hold own in server hardware") until I actually tried to run FreeBSD on modern server hardware. The Intel 10G NICs worked, but slower in benchmarks than Linux and Opensolaris. SCSI/SAS support has been rotting slowly, with the now industry-standard LSI cards I tested, working, but without interrupt coalesce and thus using more CPU and reaching only 60% of the speed of the same card in Linux or Opens…
The Intel 10G NICs worked, but slower in benchmarks than Linux and Opensolaris.
That's interesting. Which NICs are these? For most 10GbE cards we blow linux out of the water.
ZFS is less stable and slower than in OpenSolaris
That was true a couple years ago; I don't think it's true any more.
for all these years FreeBSD has lacked a journalling filesystem
True, but we've had softupdates, which is better in most circumstances. (And in HEAD we now have journalled softupdates, which gives you the best of both worlds.)
FreeBSD Jails have stagnated for years and still cannot handle running multiple copies of PostgreSQL because of SYSV support.
You have an interesting definition of "stagnate". Jails have recently gained full network stack virtualization, for instance. I can't remember if SYSV has been virtualized yet, but if not it's certainly coming soon.
I believe FreeBSD is the best and most enjoyable OS for hacking on, but this was 2 years ago, and things have further stagnated since then
Personally I'd say that the past 2 years have been the most exciting years of FreeBSD development for a long time. Maybe when 9.0 is released you'll give FreeBSD a chance again.
Re: FreeBSD on EC2 FAQ
#14I don't know much about virtualization, but could anyone explain how sites such as [1] and [2] are able to virtualize OpenBSD? Do you think they develop the Xen support internally? [1] http://bsdvm.com/ [2] http://www.rootbsd.net/blog/2010/openbsd-4-8/
Short answer: There's two types of virtualization. With full virtualization, you can run unmodified operating systems (in theory, at least). VMWare is an example of a fully virtualized system. Recently Intel and AMD added features to their CPUs which make this much easier. With para virtualization, the guest operating system is aware of the hypervisor and cooperates with it -- for example, rather than modifying page…
Great, thanks for the explanation.