FW: Copying a SolrCloud collection to other hosts

-----Original Message-----
From: Patrick Schemitz [mailto:ps@solute.de]
Sent: 06 March 2018 20:18
To: solr-user@lucene.apache.org
Subject: Copying a SolrCloud collection to other hosts

Hi List,

so I'm running a bunch of SolrCloud clusters (each cluster is: 8 shards on 2
servers, with 4 instances per server, no replicas, i.e. 1 shard per
instance).

Building the index afresh takes 15+ hours, so when I have to deploy a new
index, I build it once, on one cluster, and then copy (scp) over the
data/<main_index>/index directories (shutting down the Solr instances
first).

I could get Solr 6.5.1 to number the shard/replica directories nicely via
the createNodeSet and createNodeSet.shuffle options:

Solr 6.5.1 /var/lib/solr:

Server node 1:
instance00/data/main_index_shard1_replica1
instance01/data/main_index_shard2_replica1
instance02/data/main_index_shard3_replica1
instance03/data/main_index_shard4_replica1

Server node 2:
instance00/data/main_index_shard5_replica1
instance01/data/main_index_shard6_replica1
instance02/data/main_index_shard7_replica1
instance03/data/main_index_shard8_replica1

However, while attempting to upgrade to 7.2.1, this numbering has changed:

Solr 7.2.1 /var/lib/solr:

Server node 1:
instance00/data/main_index_shard1_replica_n1
instance01/data/main_index_shard2_replica_n2
instance02/data/main_index_shard3_replica_n4
instance03/data/main_index_shard4_replica_n6

Server node 2:
instance00/data/main_index_shard5_replica_n8
instance01/data/main_index_shard6_replica_n10
instance02/data/main_index_shard7_replica_n12
instance03/data/main_index_shard8_replica_n14

This new numbering breaks my copy script, and furthermode, I'm worried as to
what happens when the numbering is different among target clusters.

How can I switch this back to the old numbering scheme?

Side note: is there a recommended way of doing this? Is the backup/restore
mechanism suitable for this? The ref guide is kind of terse here.

Thanks in advance,

Ciao, Patrick