# Data loss after network failure
**URL:** https://discuss.elastic.co/t/data-loss-after-network-failure/20459
**Category:** Elasticsearch
**Created:** [October 28, 2014, 11:24am UTC](https://discuss.elastic.co/t/data-loss-after-network-failure/20459 "2014-10-28T11:24:52Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@Frank\_Evers](https://discuss.elastic.co/u/Frank_Evers)
#### Post date: [October 28, 2014, 11:24am UTC](https://discuss.elastic.co/t/data-loss-after-network-failure/20459/1 "2014-10-28T11:24:52Z")
Hi all,
We noticed unwanted synchronisation behaviour using two nodes with
elasticsearch-1.3.4. The nodes got disconnected from each other after a
network failure and both started running their own cluster. One node got
new data pushed to it, the other didn't. After restarting the node that got
the most recent data, it joined up with the other one. This resulted in the
loss of all the new data from the master node since the network failure.
Is this expected behaviour? If so, how can we prevent this scenario from
occurring again?
Thanks,
Frank
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### Author:  [@jprante](https://discuss.elastic.co/u/jprante)
#### Post date: [October 28, 2014, 12:52pm UTC](https://discuss.elastic.co/t/data-loss-after-network-failure/20459/2 "2014-10-28T12:52:20Z")
With two nodes, you are exposed to split brain issues, as long as you do
not set minimum\_master\_nodes = 2.
It is recommended to use an odd number of nodes and at least 3 nodes with
minimum\_master\_nodes = 2 to avoid split brain.
Jörg
On Tue, Oct 28, 2014 at 12:24 PM, Frank Evers [frankevers@voormedia.com](mailto:frankevers@voormedia.com)
wrote:
> ```
> Hi all,
>
> ```
>
> We noticed unwanted synchronisation behaviour using two nodes with
> elasticsearch-1.3.4. The nodes got disconnected from each other after a
> network failure and both started running their own cluster. One node got
> new data pushed to it, the other didn't. After restarting the node that got
> the most recent data, it joined up with the other one. This resulted in the
> loss of all the new data from the master node since the network failure.
>
> Is this expected behaviour? If so, how can we prevent this scenario from
> occurring again?
>
> Thanks,
>
> Frank
>
> --
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> [https://groups.google.com/d/msgid/elasticsearch/3bd69bfd-001c-4c62-bfde-616c1f1695c8%40googlegroups.com?utm\_medium=email&utm\_source=footer](https://groups.google.com/d/msgid/elasticsearch/3bd69bfd-001c-4c62-bfde-616c1f1695c8%40googlegroups.com?utm_medium=email&utm_source=footer)
> .
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### Author:  [@system](https://discuss.elastic.co/u/system)
#### Post date: [July 6, 2017, 12:53am UTC](https://discuss.elastic.co/t/data-loss-after-network-failure/20459/3 "2017-07-06T00:53:28Z")