On 4/19/2018 6:28 AM, Bernd Fehling wrote:
How would you setup a SolrCloud an why?
shard1 shard2 shard3
-------- -------- --------
| ---- | | ---- | | ---- |
| |r1| | | |r1| | | |r1| |
| ---- | | ---- | | ---- |
| | | | | |
| ---- | | ---- | | ---- |
| |r2| | | |r2| | | |r2| |
| ---- | | ---- | | ---- |
| | | | | |
| ---- | | ---- | | ---- |
| |r3| | | |r3| | | |r3| |
| ---- | | ---- | | ---- |
-------- -------- --------
host1 host2 host3
I'm assuming that "r1" means replica1.
If you set it up this way, you lose one third of the whole index (all
replicas of one shard) if *any* host goes down. All queries will fail
in that situation if shards.tolerant is not set. With
shards.tolerant=true, you would get partial results.
So you have three machines that are all single points of failure. This
setup is a bad idea.
-------- -------- --------
| ---- | | ---- | | ---- |
shard1 | |r1| | | |r2| | | |r3| |
| ---- | | ---- | | ---- |
| | | | | |
| ---- | | ---- | | ---- |
shard2 | |r1| | | |r2| | | |r3| |
| ---- | | ---- | | ---- |
| | | | | |
| ---- | | ---- | | ---- |
shard3 | |r1| | | |r2| | | |r3| |
| ---- | | ---- | | ---- |
-------- -------- --------
host1 host2 host3
With this setup, when any host fails, you still have two working
replicas of all shards. If two hosts fail, you still have one working
replica. There are no single points of failure, as long as your clients
are able to direct queries to a working replica. SolrJ clients using
CloudSolrClient will do this automatically. Other clients may need a
load balancer sitting in front of the cloud.
This is the recommended way of setting up replicas.
Thanks,
Shawn
