Re: [Xen-devel] [PATCH 4 of 4 V5] tools/xl: Remus - Network buffering cmdline switch

[Shriram Rajagopalan <rshriram@xxxxxxxxx>]

> >
> > Is Remus actually useable without network buffering ?  I don't think
> > we would want to change the default later, and clearly the default
> > should be to behave correctly.
> >
>
> It is usable without network buffering. Memory state is preserved on
> failover.
> On failover, without network buffering, exising network
> connectivity (tcp connections) "may" be lost, under some circumstances.

uh, wouldn't it be possible to acknowledge client requests whose
backing state hasn't been replicated? So that on failover the backup
might have no memory of a promised it had made? it's more than just
tcp resets, isn't it?

true.. which is why I stated .. 

> You are right about the fact that for Remus to behave 'correctly', one
> needs both network and disk buffering -- the latter being absent is the
> reason
> Remus in libxl is still experimental.
>
> So, might as well enable network buffering by default, punt if the support
> is
> missing and suggest that the user invoke Remus without network buffering
> (while providing sufficient warnings that the failover may be incomplete)
>

:)

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