On 1/26/23 06:26, Adam Sjøgren wrote:
We have a Solr Cloud cluster running 8.11.2 on 16 servers that have just
been upgraded to Ubuntu 20.04 (from 18.04).
It looks like we are getting shards down/recovering more often than
previously, so I'm wondering what version of Java and which garbage
collector is recommended on Ubuntu 20.04?
On https://solr.apache.org/docs/8_11_2/SYSTEM_REQUIREMENTS.html is says
Java 8 or higher - we are running 11.0.17+8-1ubuntu2~20.04.
That page also links to
https://cwiki.apache.org/confluence/display/lucene/JavaBugs which very
clearly says not to use the G1 garbage collector and that the page isn't
outdated. Hm.
Solr 8.x and later uses G1 by default. I haven't seen any problems with
it, even though Lucene recommends not using it.
For 8.x, I would use OpenJDK 11. For 9.x, OpenJDK 17.
17 might work with 8.x, but it's minimum requirement is Java 8. Jumping
a lot of major Java versions beyond the minimum requirement might cause
problems. The latest version of Solr has a workaround for a problem
with Java 17, but I don't think that workaround is there for 8.11.x.
I would choose the ZGC collector in most cases. But I have noticed that
indexing throughput is a little bit better with G1 than ZGC. If every
little bit of indexing speed is critical, stick with G1.
Thanks,
Shawn
