[dm-devel] [RFC][PATCH 0/4] dm-log: support multi-log devices

[malahal at us.ibm.com]

Takahiro Yasui [tyasui at redhat.com] wrote:
> Hi Malahal,
> 
> my patch doesn't handle transient error now. I expect log devices
> to be failed and got in a blockage status once an error has happened.
> 
> > With our user level only implementation, the log device handling would
> > be as good as the real mirror *leg* handling. We get all the benefits of
> > the mirror without doing any code! Wouldn't it be nice?
> 
> I agree that simple implementation is better, but log could be handled
> without any additional layer, and also I'm thinking that log could be
> handled in the simpler way.
> 
> Lower layer, such as SCSI, also has retry feature based on error type
> and will be done in the proper way. Do you mean that it isn't enough
> and should dm-layer handle errors for log device, too?

Not really. What I meant is re-integrating a failed log device when it
comes back again. That is also what I mean by handling 'transient
errors'.