Restore data after failover

[Lasse Schou]

Hi,

I would like to know if it is possible to restore data after a failover or if it's lost for good. Are there any tools to extract the documents from a failed-over node that hasn't been re-added into the cluster?

Thanks,

Lasse

[Aliaksey Kandratsenka]

On Sat, Mar 29, 2014 at 5:04 PM, Lasse Schou <lasse...@gmail.com> wrote:

Hi,

I would like to know if it is possible to restore data after a failover or if it's lost for good. Are there any tools to extract the documents from a failed-over node that hasn't been re-added into the cluster?

Yes it is.

On failover couchbase does not delete any data files. Just in case.

So there are multiple ways to get things back.

For example.

Option 1:

* backup data files

* rebalance node back in

* stop service on that node

* bring data files back from backup

* start service

Option 2 (in case you want to keep your recent mutations and avoid downtime):

* backup data files

* create brand new single node cluster. Possibly from failed over node.

* return files back in (note: it's important to do it after setting up node)

* create bucket

* observe log entry saying that recovery was partially successful (it'll take take subset of vbuckets from data files it sees on disk)

* xdcr data from that single node cluster back to main cluster

There are other options too. Those options look simplest.