[sheepdog-users] Understanding number of copies and offline node behaviour

[Gerald Richter - ECOS]

>On Fri, Sep 06, 2013 at 11:24:23PM +0200, Gerald Richter - ECOS wrote:
>> > 
>> > I don't think you need to reformat the cluster. 'collie cluster format -c
>> > number'
>> > this number is the default copy number for a newly created vdi, but you can
>> > actually set whatever value you want for each individual vdi.
>> > 
>> > E.g, you have a cluster formatting with '-c 2' with 4 nodes, then you can
>> > 
>> > $ collie vdi create new -c 3 # 3 copies for this new or $ collie vdi create new -c
>> > 4 # 4 copies for this new.
>> > 
>> 
>> Yes, but only for new vdi's . I have to import about 6 TByte of different vdi's to sheepdog (in a cluster that has for the start two nodes). That frees two >>additional systems, which I can add to the sheepdog cluster. So I like to bump copies from 2 to 3 and/ or set mode from unsafe to quorum, but as far as I >>understand the only chance to do so, is to export and reimport the existing vdi's . I can't do this, because I don't have 6TByte additional space...
>> 
>> How complicated would it be to add the feature to change number of copies and/or mode?
>
>Mode is removed in the recent commit. It is not hard to change copy number on
>the fly, maybe 200 lines or more, but need a good understanding of sheepdog code
>
>I think of adding this feature too, but I am busy with other features.

Since I can in 0.7.x, without problems, start with copies = 3, also I only have 2 nodes yet, this is not an issue for me anymore, but it would be nice to have, I case the cluster grows

Regards

Gerald