In general, I would avoid running 2 databases on the same server, as both use also a considerable amount of off-heap memory.
*What is your use-case / types of queries?* Not sure what version you're running as there is no 4.0.3 of Neo4j. What is your configuration of Neo4j (heap / page-cache) ? In general Neo4j benefits from having enough memory available for mapping data from disk to memory to avoid frequent seeks. The minimum you should have is 27G of heap and then page-cache of as much as possible, e.g. 80-100G on your machine (depending on your workload). Michael On Sat, Sep 16, 2017 at 2:05 AM, <rfch...@gmail.com> wrote: > Hi, > > Our hardware box has 24 cpu cores on 4 sockets,128GB RAM, 5.4TB disk. > Currently there are 962 million Nodes and 6.9 billion Relationships (!) and > growing. Neo4j databases is using 1.4TB of the disk. We are using Neo4j > 4.0.3 Community version with openjdk 1.8.0_45. > > One of our test servers used to have 10 to 15 lines of > > WARN [o.n.k.i.c.MonitorGc] GC Monitor: Application threads blocked for > xxx( e.g. 279)ms. > > in neo4j's debug.log in a day. Then, without apparent change (not we can > track from file changes), Neo4j 4.0.3 started to generate about 4,000 such > lines every day and the insertion throughput decreased drastically after > 09-06 (Sep 6th). > > We have been running two JVM's, one with Neo4j and one with Elasticsearch, > on this box for more than two months. Linux "free" command and "top" > command showed enough free RAM. vmstat doesn't show paging activities. > > Any idea how to prevent this frequent GC from happening in Neo4j/JVM? Is > it a bad idea to run two JVM's on the sam server? > > Thanks, > Ray > > > -- > You received this message because you are subscribed to the Google Groups > "Neo4j" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to neo4j+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "Neo4j" group. To unsubscribe from this group and stop receiving emails from it, send an email to neo4j+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
