On 8/29/2021 2:38 AM, HariBabu kuruva wrote:
Is it required to define both the parameters SOLR_HEAP and SOLR_JAVA_MEM.
or can i comment SOLR_HEAP and only define SOLR_JAVA_MEM.
Also what highest value of Xmx value i can go if i receive OOM with 31gb.
I have only solr running on that node.
If both are defined, I do not know which one will actually take effect.
Figuring that out would require looking at the startup script and
doing some experiments to see what Java actually does.
I would personally remove SOLR_JAVA_MEM and only go with SOLR_HEAP.
Then you can do something very simple like the following, and the Solr
startup script will set both -Xms and -Xmx java options to that value:
SOLR_HEAP=4g
And could you please let me know the reason to disable swap memory.
If a system starts actively swapping, its performance in general will be
extremely low. If that happens, it is an indication that there is not
enough physical memory and the system needs more, or that configurations
need to be adjusted to require less memory.
Disabling swap makes it impossible for the OS to try and use disk space
as memory. In situations where programs are asking for too much memory
and you have swap completely disabled, either Java or the OS will simply
kill the process that's asking for too much memory, rather than letting
it run and destroy overall performance.
---
Responding to something in the OP:
It is completely normal to see 100 percent memory utilization on just
about any server, whether it's running Solr or not. The OS will use all
available memory for caching purposes, to speed everything up. The only
time you won't see 100 percent memory usage is when you have far more
memory than the system actually needs. For instance, if you had 512GB
of memory on a system that only handles megabytes of data.
https://cwiki.apache.org/confluence/display/solr/SolrPerformanceProblems
(disclaimer: I wrote the wiki page linked here. Any errors are mine.)
Thanks,
Shawn
