[Gluster-users] ... i was able to produce a split brain...

[Joe Julian]

Looks good! 

On January 30, 2015 4:58:35 AM PST, Jeff Darcy <jdarcy at redhat.com> wrote:
>> Pranith and I had a discussion regarding this issue and here is what
>we have
>> in our mind right now.
>> 
>> We plan to provide the user commands to execute from mount so that he
>can
>> access the files in split-brain. This way he can choose which copy is
>to be
>> used as source. The user will have to perform a set of getfattrs and
>> setfattrs (on virtual xattrs) to decide which child to choose as
>source and
>> inform AFR with his decision.
>> 
>> A) To know the split-brain status :
>> getfattr -n trusted.afr.split-brain-status <path-to-file>
>> 
>> This will provide user with the following details -
>> 1) Whether the file is in metadata split-brain
>> 2) Whether the file is in data split-brain
>> 
>> It will also list the name of afr-children to choose from. Something
>like :
>> Option0: client-0
>> Option1: client-1
>> 
>> We also tell the user what the user could do to view metadata/data
>info; like
>> stat to get metadata etc.
>> 
>> B) Now the user has to choose one of the options
>(client-x/client-y..) to
>> inspect the files.
>> e.g., setfattr -n trusted.afr.split-brain-choice -v client-0
><path-to-file>
>> We save the read-child info in inode-ctx in order to provide the user
>access
>> to the file in split-brain from that child. Once the user inspects
>the file,
>> he proceeds to do the same from the other child of replica pair and
>makes an
>> informed decision.
>> 
>> C) Once the above steps are done, AFR is to be informed with the
>final choice
>> for source. This is achieved by -
>> (say the fresh copy is in client-0)
>> e.g., setfattr -n trusted.afr.split-brain-heal-finalize -v client-0
>> <path-to-file>
>> This child will be chosen as source and split-brain resolution will
>be done.
>
>+1
>
>That looks quite nice, and AFAICT shouldn't be prohibitively hard to
>implement.

-- 
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