The way I see block filter currently implemented is as a special block
device
with `is_filter` set to true.
Is this a correct characterization of the current incarnation?
If so, I was wondering if it is possible to "insert" a block filter layer
on top
of an existing block device once QEMU is exec
On Sat, Oct 12, 2013 at 1:47 AM, Fam Zheng wrote:
> While mirroring write is a good idea, doing it with drive-backup is probably
> not. The function of this command is to 'backup' the image with existing data,
> instead of new data. With your 'stream' mode, this semantic is changed.
I'm not so su
On Fri, Oct 11, 2013 at 11:38 AM, Eric Blake wrote:
> On 10/11/2013 09:18 AM, Wolfgang Richter wrote:
>> Idea: Introduce a mode for drive-backup that duplicates writes to
>> another target, not CoW. It is useful for introspecting (my use
>> case), and for keeping a remote
Idea: Introduce a mode for drive-backup that duplicates writes to
another target, not CoW. It is useful for introspecting (my use
case), and for keeping a remote block device in sync with writes
(helps with migration or backup).
Issue with current modes: All of the current modes are well-desig
On Mon, Sep 30, 2013 at 3:41 AM, Paolo Bonzini wrote:
> Il 30/09/2013 00:46, Wolfgang Richter ha scritto:
> All writes to the drive-backup source have to first copy the pre-write
> data to the target. Thus, drive-backup usually works best if you are
> using werror=stop on the source
I wanted to explore overhead with the new drive-backup command and I
noticed if I set the target to something like '/dev/null' the guest VM
starts having IO errors and loses write access to its root file
system. Here is the qmp-shell command I'm using:
> drive-backup sync=none device=virtio0 targ
On Wed, May 22, 2013 at 3:26 PM, Richard W.M. Jones wrote:
> On Wed, May 22, 2013 at 02:32:37PM -0400, Wolfgang Richter wrote:
> > On Wed, May 22, 2013 at 12:42 PM, Richard W.M. Jones >wrote:
> >
> > > Run up to two extra guestfish instances, with the same result.
I am in charge of a workshop happening at CMU with
21 guests currently registered.
It will be on using QEMU/KVM, coding inside those codebases,
using libvirt, and possibly OpenStack.
We will have several talks during the day on how people have
used QEMU + KVM in their own research, tips and trick
On Wed, May 22, 2013 at 12:42 PM, Richard W.M. Jones wrote:
> Run up to two extra guestfish instances, with the same result. The
> fourth guestfish instance hangs at the 'run' command until one of the
> first three is told to exit.
And your interested on being notified when a snapshot is "safe"
On Wed, May 22, 2013 at 12:11 PM, Paolo Bonzini wrote:
> > Essentially, if you're RWMJ (not me), and you're keeping a full
> > mirror, it's clear that the mirror write stream goes to an nbd server,
> > but is it possible to attach a reader to that same nbd server and read
> > things back (read-on
On Thu, May 16, 2013 at 9:44 AM, Richard W.M. Jones wrote:
> Ideally I'd like to issue some QMP commands which would set up the
> point-in-time snapshot, and then connect to this snapshot over (eg)
> NBD, then when I'm done, send some more QMP commands to tear down the
snapshot.
>
This is actual
On Wed, May 15, 2013 at 7:54 AM, Paolo Bonzini wrote:
> > But does this really cover all use cases a real synchronous active
> > mirror would provide? I understood that Wolf wants to get every single
> > guest request exposed e.g. on an NBD connection.
>
> He can use throttling to limit the guest
On Tue, May 14, 2013 at 12:45 PM, Paolo Bonzini wrote:
> No, I'll just reuse the same hooks within block/mirror.c (almost... it
> looks like I need after_write too, not just before_write :( that's a
> pity). Basically:
>
> 1) before the write, if there is space in the job's buffers, allocate a
>
On Tue, May 14, 2013 at 6:04 AM, Paolo Bonzini wrote:
> Il 14/05/2013 10:50, Kevin Wolf ha scritto:
> > Or, to translate it into our existing terminology, drive-mirror
> > implements a passive mirror, you're proposing an active one (which we
> > do want to have).
> >
> > With an active mirror, we
On Tue, May 14, 2013 at 4:50 AM, Kevin Wolf wrote:
> Or, to translate it into our existing terminology, drive-mirror
> implements a passive mirror, you're proposing an active one (which we
> do want to have).
>
> With an active mirror, we'll want to have another choice: The mirror can
> be synchr
On Tue, May 14, 2013 at 4:40 AM, Stefan Hajnoczi wrote:
> QEMU is accumulating many different approaches to snapshots and
> mirroring. They all have their pros and cons so it's not possible to
> support only one approach for all use cases.
>
> The suggested approach is writing a BlockDriver which
On May 13, 2013, at 5:46 PM, "Richard W.M. Jones" wrote:
> On Mon, May 13, 2013 at 01:50:00PM -0400, Wolfgang Richter wrote:
>> Paolo/anyone who knows -
>>
>> Are drive-mirror sync points (NBD flush commands) reflecting guest write
>> barriers? Are gu
I'm working on a new patch series which will add a new QMP command,
block-trace, which turns on tracing of writes for a specified block device
and
sends the stream unmodified to another block device. The 'trace' is meant
to
be precise meaning that writes are not lost, which differentiates this
com
Paolo/anyone who knows -
Are drive-mirror sync points (NBD flush commands) reflecting guest write
barriers? Are guest write barriers respected by drive-mirror? If so, that
would make drive-mirror much more palatable for disk introspection work (a
drop-in usable feature of QEMU!).
--
Wolf
On Wed, Apr 24, 2013 at 1:37 AM, Stefan Hajnoczi wrote:
> I think what you really want is a "tap" block driver which mirrors
> writes to a target device (typically a NBD volume). You can model this
> on blkverify or check out Benoit Canet's quorum patches.
>
> Stefan
>
An interesting thought, w
On Wed, Apr 24, 2013 at 12:15 PM, Paolo Bonzini wrote:
> Il 24/04/2013 18:12, Wolfgang Richter ha scritto:
> > In the purest form, not to miss "updates" I'm not OK with it. But, I
> think
> > that introspection can still _mostly_ work given these relaxed
> c
On Wed, Apr 24, 2013 at 5:26 AM, Paolo Bonzini wrote:
> Il 23/04/2013 20:31, Wolfgang Richter ha scritto:
> > On Tue, Apr 23, 2013 at 2:21 PM, Stefan Hajnoczi > <mailto:stefa...@gmail.com>> wrote:
> >
> > The tracing subsystem is geared towards tracepoint in
On Wed, Apr 24, 2013 at 5:24 AM, Paolo Bonzini wrote:
> Il 24/04/2013 10:37, Stefan Hajnoczi ha scritto:
> >> > Has there been any performance analysis of drive-mirror (impact on
> executing guest)?
>
> What Stefan wrote is about block-backup.
>
> drive-mirror has a limited impact on guest perfor
On Wed, Apr 24, 2013 at 4:39 AM, Stefan Hajnoczi wrote:
> On Tue, Apr 23, 2013 at 03:11:26PM -0400, Wolfgang Richter wrote:
> > On Tue, Apr 23, 2013 at 2:31 PM, Wolfgang Richter
> wrote:
> >
> > > On Tue, Apr 23, 2013 at 2:21 PM, Stefan Hajnoczi >wrote:
> &g
On Wed, Apr 24, 2013 at 4:37 AM, Stefan Hajnoczi wrote:
> > Has there been any performance analysis of drive-mirror (impact on
> executing guest)?
>
> It slows down guest I/O for a couple of reasons:
>
> 1. Writes now require a read from the original device followed by a
>write to the target
--
Wolf
On Apr 23, 2013, at 1:22 PM, Eric Blake wrote:
> On 04/23/2013 11:12 AM, Wolfgang Richter wrote:
>> I'm interested in adding introspection of disk writes to QEMU for various
>> applications and research potential.
>>
>> What I mean by introspection of d
On Tue, Apr 23, 2013 at 2:31 PM, Wolfgang Richter wrote:
> On Tue, Apr 23, 2013 at 2:21 PM, Stefan Hajnoczi wrote:
>
>> Eric's suggestion to use NBD makes sense to me. The block-backup code
>> can be extended fairly easier using sync mode=none (do not perform a
>>
On Tue, Apr 23, 2013 at 2:21 PM, Stefan Hajnoczi wrote:
> The tracing subsystem is geared towards tracepoint instrumentation
> rather than binary dumps.
>
> Can you share some specific applications?
>
Well, my main application is in exposing a "cloud-inotify" service by
interpreting
sector write
I'm interested in adding introspection of disk writes to QEMU for various
applications and research potential.
What I mean by introspection of disk writes is that, when enabled, each
write
passing through QEMU to backing storage would also be copied to an
introspection channel for further analysis
Is it possible to network multiple sessions of QEMU so they appear to be
on the same simulated network?
--
Wolfgang Richter
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NIC's??
Wolfgang Richter wrote:
>Basically, what I want to accomplish is this. eth0 and eth1 are in
>bridging mode, with eth0 supposedly leading out to the internet, and
>eth1 supposedly connecting an internal network to the internet. eth2
>connects to a third network, but th
I am assuming the nics work with -user-net properties, with a simulated
router/firewall DHCP server at 10.0.2.2. Is it possible to manually
assign an IP (such as 10.0.2.5; is 10.0.2.3 still a nameserver?) and
still have access to the internet?
Wolfgang Richter wrote:
>Basically, what I want
a few ports open and so does eth2. Is this possible at all
with QEMU? So far I've had no luck...but will continue trying different
configurations.
--
Wolfgang Richter
[EMAIL PROTECTED] wrote:
>I am trying to simulate three NIC's, with redirected ports from the host to my
>simulate
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