Re: linux dom0 versus NetBSD dom0

[Adam Hamsik <haaaad%gmail.com@localhost>]

On Jan,Thursday 12 2012, at 9:32 PM, Luke S. Crawford wrote:

> On Wed, Jan 11, 2012 at 01:37:47PM -0800, Brian Buhrow wrote:
>> 4.  Are there folks who have experience running Xen with NetBSD and Linux
>> who would care to comment on their experience with each?
> 
> 
> I used NetBSD/Xen way back in the NetBSD3.1/xen 2  days.   It was
> actually pretty solid, way more so than the Linux Dom0s of the time.
> The problem was back then that it was i386/non-PAE only, which caused
> all kinds of problems at the time.  Also, the ext2 utilities did not
> work well with ext3 filesystems.
> 
> We switched to Linux Dom0s before pae was stable because that's 
> a showstopper when you want hardware with more than 4G ram. We 
> haven't switched back yet.  (you can run a i386-PAE dom0 on a x86_64
> hypervisor, but if you want a non-pae dom0 you must have a non-pae
> i386 hypervisor.   I think the xen.org people stopped supporting
> the non-pae i386 hypervisor some time ago.  But in '04-'05, that's what
> I was using in production, and other than the ram limits, it was solid
> and customers seemed to be much happier than on my previous FreeBSD
> Jails.)   
> 
> Of course, now NetBSD supports PAE and x86_64, so I've kinda
> been looking back every now and then.   One big problem I still
> see is that NetBSD doesn't have anything like LVM (oh man, if netbsd
> had stable zfs, I'd switch back in a nanosecond.)  so you are stuck
> with loopback mount files,  which might be okay;  I mean, that's what
> I used back in the day and it was okay.   There is a really old benchmark
> showing that xen guests backed by loopback mount files were way faster
> on NetBSD than on Linux, but on linux you'd use something like Tap:AIO
> which as far as I know, NetBSD lacks, so you wouldn't use loopback
> mounted files on linux anyhow, so it's not really a fair comparison.
> (this bench might have been before tap:aio, so it very well could
> have been a fair comparison at the time.)  

Netbsd 6 will have stable LVM implementation compatbile with linux.
ZFS zpool should be stable, too. FS is part of zfs which is
unstable now.

Regards

Adam.