On 02/28/2011 07:33 PM, Anthony Liguori wrote:
>
> You're just ignoring what I've written.
No, you're just impervious to my subtle attempt to refocus the
discussion on solving a practical problem.
There's a lot of good, reasonably straight forward changes we can make
that have a high return on investment.
Is making qemu the authoritative source of configuration information a
straightforward change? Is the return on it high? Is the investment low?
"No" to all three (ignoring for the moment whether it is good or not,
which we were debating).
The only suggestion I'm making beyond Marcelo's original patch is that
we use a structured format and that we make it possible to use the
same file to solve this problem in multiple places.
No, you're suggesting a lot more than that.
I don't think this creates a fundamental break in how management tools
interact with QEMU. I don't think introducing RAID support in the
block layer is a reasonable alternative.
Why not?
Something that avoids the whole state thing altogether:
- instead of atomically switching when live copy is done, keep on
issuing writes to both the origin and the live copy
- issue a notification to management
- management receives the notification, and issues an atomic blockdev
switch command
this is really the RAID-1 solution but without the state file (credit
Dor). An advantage is that there is no additional latency when trying
to catch up to the dirty bitmap.
--
error compiling committee.c: too many arguments to function
