Hi there,
I'm currently using solr v7.7.2 *(I applied the patch SOLR-13674
<https://issues.apache.org/jira/browse/SOLR-13674> to my build to preserve
replica types for triggers)* and trying to set up a cluster with the
combination of TLOG+PULL replicas and utilising the solr autoscaling
feature to maintain the stability of the cluster.
I'm getting confused though with the documentation.
When creating a collection, if you specify "replicationFactor=3" then it'll
create 3 NRT replicas, and from my understanding, this information is
preserved within autoscaling, i.e. if a node went down, it would attempt to
add another replica to preserve the replicationFactor.
However, because I'm using TLOG + PULL, I don't add the
"replicationFactor=3" into my collection creation, otherwise it ends up
creating a collection with 3 NRT replicas, 1 TLOG and 2 PULL replicas,
which of course I do not want.
Instead, I add "&tlogReplicas=1&pullReplicas=2" which satisfies. However,
when it comes to me creating policies, I'm not getting violations when
expected.
I created the following policies:
{
"replica": "<2",
"shard": "#EACH",
"type": "TLOG",
"node": "#ANY"
},
{
"replica": "<3",
"shard": "#EACH",
"type": "PULL",
"node": "#ANY"
}
And there appears to be 0 violations, however, when I add another replica,
there are still 0 violations despite there now being 4 replicas for a given
shard of a collection;
"violations":[],
"config":{
"cluster-preferences":[{
"minimize":"cores",
"precision":1}
,{
"maximize":"freedisk"}],
"cluster-policy":[{
"replica":"<2",
"shard":"#EACH",
"type":"TLOG",
"node":"#ANY"}
,{
"replica":"<3",
"shard":"#EACH",
"type":"PULL",
"node":"#ANY"}]}},
And here is the information about a collection-shard in which I added an
extra replica to which I expected there to be a violation:
{
"replica_p35": {
"core": "collection_four_shard1_replica_p35",
"shard": "shard1",
"collection": "collection_four",
"state": "active",
"shard_name": "collection_four_shard1",
"num_shards": 6,
"type": "PULL"
},
"replica_p31": {
"core": "collection_four_shard1_replica_p31",
"shard": "shard1",
"collection": "collection_four",
"state": "active",
"shard_name": "collection_four_shard1",
"num_shards": 6,
"type": "PULL"
},
"replica_p87": {
"core": "collection_four_shard1_replica_p87",
"shard": "shard1",
"collection": "collection_four",
"state": "active",
"shard_name": "collection_four_shard1",
"num_shards": 6,
"type": "PULL"
},
"replica_t75": {
"core": "collection_four_shard1_replica_t75",
"shard": "shard1",
"collection": "collection_four",
"state": "active",
"shard_name": "collection_four_shard1",
"type": "TLOG",
"leader": "true"
}
}
Am I missing something to preserve replicationFactor for a collection, and
trying to make collections have 1 TLOG replica and 2 PULL replicas?
I tried adding the following
{"replicas": "<4", "shard":"#EACH", "node": "#ANY"}
However, still no luck
Equally, how would I then go about setting up triggers to only create a
PULL if a PULL goes down, and equally if the TLOG goes down? Would having a
trigger for each type be needed?
Any guidance on this would be greatly appreciated
Thanks,
--
Richard Goodman
