Re: [Xen-devel] [PATCH v2 COLOPre 11/13] tools/libxl: rename remus device to checkpoint device

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Jun 15, 2015 at 09:45:54AM +0800, Yang Hongyang wrote:
> 
> 
> On 06/12/2015 10:57 PM, Ian Jackson wrote:
> >Wei Liu writes ("Re: [Xen-devel] [PATCH v2 COLOPre 11/13] tools/libxl: 
> >rename remus device to checkpoint device"):
> >>On Fri, Jun 12, 2015 at 02:30:46PM +0100, Wei Liu wrote:
> >>>On Mon, Jun 08, 2015 at 11:43:15AM +0800, Yang Hongyang wrote:
> >>>>-    (-18, "REMUS_DEVOPS_DOES_NOT_MATCH"),
> >>>>-    (-19, "REMUS_DEVICE_NOT_SUPPORTED"),
> >>>>+    (-18, "CHECKPOINT_DEVOPS_DOES_NOT_MATCH"),
> >>>>+    (-19, "CHECKPOINT_DEVICE_NOT_SUPPORTED"),
> >>>
> >>>You should add two new error numbers.
> >>>
> >>
> >>And in that case you might also need to go through all places to make
> >>sure the correct error numbers are return. I.e. old remus code path
> >>still returns REMUS error code and new CHECKPOINT code path returns new
> >>error code.
> >>
> >>I merely speak from API backward compatibility point of view. If you
> >>think what I suggest doesn't make sense, please let me know.
> >
> >To me this line of reasons prompts me to ask: what would be wrong with
> >leaving the word REMUS in the error names, and simply updating the
> >descriptions ?
> >
> >After all AFIACT the circumstances are very similar.  I don't think it
> >makes sense to require libxl to do something like
> >    rc = were_we_doing_colo_not_remus ? CHECKPOINT_BLAH : REMUS_BLAH;
> >
> >Please to contradict me if I have misunderstood...
> 
> COLO and REMUS both are checkpoint device. We use checkpoint device layer
> as a more abstract layer for both COLO and REMUS, come to the error code,
> these can be used by both COLO and REMUS. So we don't distinguish if we
> are doing COLO or REMUS, uses are aware of what they're executing(colo
> or remus).
> 

Right. So continue using REMUS_ error code is fine.

Wei.

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