[9fans] QEMU and Venti

[9fans] QEMU and Venti

[Pietro Gagliardi]

Hello. Someone just told me the fault on why QEMU crashes every time I
boot Plan 9 -- venti. With a fossil only system, everything worked
without a hitch -- until that corrupt root entry fiasco which cost me
a book I was writing, a troff preprocessor (eg, for graphing
equations), my extensions to hoc(1), and other items. So I went to
fossil+venti, suffered several crashes on Tiger but little else, then
went to Leopard to find out that it always crashed. So I'll go back to
fossil-only and be locked in prayer that it doesn't happen again. I
have no knowledge of filesystem design so I can't help with venti. -
Pietro

Re: [9fans] QEMU and Venti

[Jeff Sickel]

On Apr 22, 2008, at 3:19 PM, Pietro Gagliardi wrote:

> Hello. Someone just told me the fault on why QEMU crashes every time
> I boot Plan 9 -- venti. With a fossil only system, everything worked
> without a hitch -- until that corrupt

On Leopard I've found that QEMU runs very slowly but crashes
exceedingly reliably.  So much so, that it wasn't worth my effort to
get Plan 9 or anything else running on it for much time at all.  With
luck and a lot of trying, I did get VMware to work very reliably with
Plan 9--I've got it running right now to look at all the nice details
about grabrfc currently floating about.

Note: for VMware it helps to set it up with pccpuf and modify the boot
to not bring up rio.  Keep the console running and use drawterm
instead and it works like a charm.

-jas

Re: [9fans] QEMU and Venti

[Russ Cox]

> Hello. Someone just told me the fault on why QEMU crashes every time I
> boot Plan 9 -- venti. With a fossil only system, everything worked
> without a hitch -- until that corrupt root entry fiasco which cost me
> a book I was writing, a troff preprocessor (eg, for graphing
> equations), my extensions to hoc(1), and other items. So I went to
> fossil+venti, suffered several crashes on Tiger but little else, then
> went to Leopard to find out that it always crashed. So I'll go back to
> fossil-only and be locked in prayer that it doesn't happen again.

Prayer is one option; backups are a better one.

Normally I'm quite sympathetic to stories about losing files,
but ultimately, you have to take responsibility for your own
actions.  You chose to trust the only copy of your important
files to a single disk, without backups.  Further, you picked
a system that you had little to no experience using and no
reason to believe would run reliably.  You made a giant chain
of possible single points of failure -- fossil, venti, QEMU, OS X,
your disk -- and assumed that none of them would fail.
But one did.  Losing data always sucks, but you set yourself
up for it.

Fossil and venti have had their share of bugs, and if I thought
you had run into one, I would be working hard to find and fix it.
But right now, all evidence points to QEMU or hardware errors.

It is entirely believable that QEMU does crash when running
venti -- I've crashed it doing many things -- but that doesn't
imply that venti is broken.  It implies that QEMU is broken.
If you want to run Plan 9 reliably, find a way to do it on a more
reliable set up, one that doesn't include QEMU.

Russ