[sheepdog-users] Stop cluster when missing node == n copies

Liu Yuan namei.unix at gmail.com
Wed Sep 11 12:34:54 CEST 2013

On Wed, Sep 11, 2013 at 10:13:44AM +0200, Valerio Pachera wrote:
> 2013/9/10 Liu Yuan <namei.unix at gmail.com>:
> > from who this node can recovery objects? There is only one node left. Please try
> > this, 4 nodes with 2 copies and kill 2 nodes at the same time.
> > 3 nodes fail at the same time and if one of them can get back after failure then
> > you don't lose any data.
> That's the thing I'm trying to clarify: what happens when too many
> nodes fails at the same time?
> Using the last example (9 node, copies 3, 3 nodes failing): what
> happens if I can't restore (in short time) any of the 3 failed nodes?

First of all, vdi is striped into 4M objects (fixed length of chunk). So
objects that happen to have 3 copies on these 3 nodes, then it will get lost.

Sheepdog will try to recover objects that are lost when you get failed nodes
back later.


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