Skip site navigation (1)Skip section navigation (2)
Date:      Mon, 13 Dec 2010 20:07:05 +0000
From:      "Robert N. M. Watson" <rwatson@FreeBSD.org>
To:        Ion-Mihai Tetcu <itetcu@FreeBSD.org>
Cc:        "svn-src-stable@freebsd.org" <svn-src-stable@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "Robert N. M. Watson" <rwatson@FreeBSD.org>, "svn-src-stable-8@freebsd.org" <svn-src-stable-8@freebsd.org>
Subject:   Re: svn commit: r216406 - stable/8/sys/amd64/conf
Message-ID:  <A27FD2F0-A422-4735-B5EE-5FA59639F3E7@FreeBSD.org>
In-Reply-To: <20101213202830.75fbce4c@it.buh.tecnik93.com>
References:  <201012131234.oBDCYZvl082510@svn.freebsd.org> <20101213160021.60401b79@it.buh.tecnik93.com> <B7ED1E1F-5797-448E-A1A7-D905E7EE5FD5@FreeBSD.org> <20101213202830.75fbce4c@it.buh.tecnik93.com>

next in thread | previous in thread | raw e-mail | index | archive | help
On 13 Dec 2010, at 18:28, Ion-Mihai Tetcu <itetcu@FreeBSD.org> wrote:

> I see. Thanks for the time you took to explain things, I'm very new to
> XEN.
> Do we have any docs somewhere (well, except the sources) about our XEN
> support and various options / optimizations? I only know about
> AdrianChadd's wiki pags and http://wiki.freebsd.org/FreeBSD/Xen (which
> are nice, if you happen to know about XEN already and especially if you
> want to work towards a FreebSD as XEN host).
> I guess there are more interested people taht want just to run FreeBSD
> as guest OS (my case).
>>=20

The current state of our Xen documentation is ... minimalist. Having basical=
ly come to it for the first time last week, when we decided we needed to dep=
loy FreeBSD on one of our Xen server pools, it's proven pretty hard-going. I=
 have some more technical problems to resolve but high on my todo list for t=
he next couple of days is documenting what has worked for me on the Wiki (wi=
th the intent of migrating that to the Handbook once I've confirmed my instr=
uctions are reproducible!). I also want to drop in at least some stub man pa=
ges for our PV drivers.

However, more fundamentally, we appear to have some serious functional gaps:=


- No ability to use PV drivers under HVM on i386.
- No ability to use a full PV kernel for amd64 (I don't consider this a prob=
lem for my use though -- HVM on amd64 appears to work well).
- No (obvious) port of Xen guest command line tools to steer ballooning, etc=
.
- Likely under-testing in certain PV drivers, such as the balloon driver.
- A possible issue with VM migration on PV i386 (we saw panics in local test=
ing, but now wonder I it was an unrelated issue relating to different CPU ty=
pes -- more investigation due).
- No event mechanism for blkfront to propagate block device expansion up the=
 geom stack, in support of live file system resizing. Right now a destructiv=
e orphan/retaste is required.
- No live file system resizing support in UFS (does work in ZFS).
- No reference "appliance" images for VM starting points (really requires li=
ve file system resizing to be useful). This was a top request o our admin fo=
lks.

All this said, and after quite a lot of head-scratching, FreeBSD/amd64 seems=
 to work well on Xen here a Cambridge, both with and without Xen PV drivers c=
ompiled in. We need a lot of sanding and polishing but the foundations have b=
een usefully laid. And I would agree that documentation is key.

Robert=



Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?A27FD2F0-A422-4735-B5EE-5FA59639F3E7>