On Wed, Apr 23, 2008 at 7:53 PM, erik quanstrom <[EMAIL PROTECTED]> wrote:
>
> what i'm saying is boils down to 10ms + 100ns is essentially 10ms.
> so it's slower, but at a level a couple (or three) orders of magnitude too
> low to be very significant.
>
ah, but its not always 10ms because of the page cache...but I'm
digressing to a new low level. Actually, the argument that Ron and I
both made is that they should ditch both the network and the block
(and the console) drivers/protocols and just use 9p for all three. It
adds your slight 100ns of overhead, but unifies all God's children.
However, given that the virtio stuff is infinitely better than the Xen
approach and the other craptastic virtualization I/O schemes, we
decided to leave well enough alone and do the 9p stuff ourselves
(which begs the question why Ron is using the disk and net drivers and
not the superior 9p driver, but I digress yet again).
> > [...] adding extra layers for nothing.
>
> avoiding maintaing a second interface doesn't count? and according
> to ron, the network is fast right now. this virtual ata interface isn't.
>
come back to his jebus and remember that the only real goal of all
virtualization people is to support windows -- they'll always have a
block device. It will get faster, you can hear the millions of
monkey's typing in the distance.
>
> now i'm really dreaming but ... why don't you convince the virtualizer guys
> to implement aoe instead of a straight ata interface for high performance.
> it would be less work for them too, and would eliminate the extra layer --
> vblade.
>
I misled you a bit when I said it was AOV, its actually much closer to
just the straight block device. No real naming issues and it
back-ends into a bunch of stuff they want like copy-on-write and what
not. WAIT - I already hear you complaining about my lack of
consistency because I was talking about kernel-cut-thru's -- however,
the nature of the game is there are several back-ends for several
different solutions. I like AOE, I think its a great general
solution, but I don't see it solving their problems and it complicates
some of their security, failover and migration schemes. Its close to
the equivalent of saying why doesn't Linux use AOE as its block driver
interface.
-eric
