Hi,

Can anyone help me. I'm trying (and failing) to move my 3 node C* data from my 
Production Environment to my Development 3 node cluster.

Here is the fine print...

Oracle Linux 7.3
C* 3.0.11

3 Nodes ((virtual Nodes 256))
1 Keyspace (replication factor 3) Quorum Consistency
1 table

Snapshot taken on each node.

Attempt 1

I've tried the following 
(http://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsSnapshotRestoreNewCluster.html)



  1.  From the old cluster, retrieve the list of tokens associated with each 
node's IP:

$ nodetool ring | grep ip_address_of_node | awk '{print $NF ","}' | xargs



I've done this for all 3 nodes, placed them together in one string

  1.  In the 
cassandra.yaml<http://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsSnapshotRestoreNewCluster.html#opsSnapshotRestoreNewCluster__cassandrayaml>
 file for each node in the new cluster, add the list of tokens you obtained in 
the previous step to the 
initial_token<http://docs.datastax.com/en/cassandra/3.0/cassandra/configuration/configCassandra_yaml.html#configCassandra_yaml__initial_token>
 parameter using the same num_tokens setting as in the old cluster.
Added all the tokens from step one

  1.  Make any other necessary changes in the new cluster's 
cassandra.yaml<http://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsSnapshotRestoreNewCluster.html#opsSnapshotRestoreNewCluster__cassandrayaml>
 and property files so that the new nodes match the old cluster settings. Make 
sure the seed nodes are set for the new cluster.
  2.  Clear the system table data from each new node:

$ sudo rm -rf /var/lib/cassandra/data/system/*

This allows the new nodes to use the initial tokens defined in the 
cassandra.yaml<http://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsSnapshotRestoreNewCluster.html#opsSnapshotRestoreNewCluster__cassandrayaml>
 when they restart.

  1.  Start each node using the specified list of token ranges in new cluster's 
cassandra.yaml<http://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsSnapshotRestoreNewCluster.html#opsSnapshotRestoreNewCluster__cassandrayaml>:

initial_token: -9211270970129494930, -9138351317258731895, 
-8980763462514965928, ...

  1.  Create schema in the new cluster. All the schemas from the old cluster 
must be reproduced in the new cluster.
  2.  Stop the 
node<http://docs.datastax.com/en/cassandra/3.0/cassandra/initialize/referenceStartStopTOC.html>.
 Using nodetool refresh is unsafe because files within the data directory of a 
running node can be silently overwritten by identically named just-flushed 
SSTables from memtable flushes or compaction. Copying files into the data 
directory and restarting the node will not work for the same reason.
  3.  Restore the SSTable files 
snapshotted<http://docs.datastax.com/en/cassandra/3.0/cassandra/operations/opsBackupSnapshotRestore.html>
 from the old cluster onto the new cluster using the same directories, while 
noting that the UUID component of target directory names has changed. Without 
restoration, the new cluster will not have data to read upon restart.
  4.  Restart the node.

When  I restart I get errors in the Yaml file pointing to the token ranges.

If I take out the tokens for 2 of the nodes and just use one node(s) tokens I 
can restore the data, but I get only a third of the row count id expect.

I then noticed I was only restoring  the snapshot from that one node, so , that 
made sense....

So then I took all of the snapshots, from all of the nodes, placed them into a 
folder, re added all the tokens and re ran the process, but I get the token 
range error in the yaml again.


Attempt 2

So then I tried  SSTableLoader from the same folder with all the (3 nodes 
snapshots) and then I get corruption on the SSTable..


Advice

I've tried this so many ways its getting confusing.. what's right?

Can anyone give me some pointers as to the best route to migrate data from 
cluster to cluster? The Documentation is so vague and not detailed enough?

Do I copy the snapshots from all the nodes?
Do I just work on one node at a time?

Any suggestions please??

Thanks
J



Jonathan Baynes
DBA
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