Re: [PATCH 26/30] ext4: do not send discards as barriers

[Vladislav Bolkhovitin]

Jan Kara, on 08/31/2010 12:20 AM wrote:
> On Mon 30-08-10 15:56:43, Jeff Moyer wrote:
> > Jan Kara<jack@xxxxxxx>  writes:
> >
> > >    An update: I've set up an ext4 barrier testing in KVM - run fsstress,
> > > kill KVM at some random moment and check that the filesystem is consistent
> > > (kvm is run in cache=writeback mode to simulate disk cache). About 70 runs
> >
> > But doesn't your "disk cache" survive the "power cycle" of your guest?
>    Yes, you're right. Thinking about it now the test setup was wrong because
> it didn't refuse writes to the VM's data partition after the moment I
> killed KVM. Thanks for catching this. I will probably have to use the fault
> injection on the host to disallow writing the device at a certain moment.
> Or does somebody have a better option?

Have you considered to setup a second box as an iSCSI target (e.g. with 
iSCSI-SCST)? With it killing the connectivity is just a matter of a 
single iptables command + a lot more options.

Vlad
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/