[Sheepdog] Option 'copies'

[Valerio Pachera]

>From getting started:
'It is enough to run this command on one of machines. "--copies"
specifies the number of default data redundancy. In this case, the
replicated data will be stored on three machines.'

Correct me if I'm wrong: using --copies=3, I have always at least 3
copies for any chunck of a vdi disk.
So, if my scluster uses 5 or more nodes, when one of them dies, the
chunks stored on will be moved to the other nodes.

The chunks are distrubted  on all nodes. So I do not have 3 nodes with
data and 2 without.

If I add a node (the 6th) simply by "sheep /speed_data", the chinks
will automatically be distrbuted also on the new node.

If I shutdown a node after the other, giving it the time necessesary
for data sync, all the data will be move to the last node (off course
with enough space).
There will be no redudance and the last node will not have any 'extra'
chunk copy left.

In this schenario, one node "exports" one directory, so removing a
node equals to remve a "cluster member". Anyway, a single node can
export more directories so ti would be more correct to speak about
"removing directory form the cluster"?

Thanks.