Run a GC analyzer on that JVM. I cannot imagine that they need 80 GB of heap. I’ve never run with more than 16 GB, even for a collection with 70 million documents.
Look at the amount of heap used after full collections. Add a safety factor to that, then use that heap size. wunder Walter Underwood wun...@wunderwood.org http://observer.wunderwood.org/ (my blog) > On Oct 6, 2022, at 2:54 PM, Dominique Bejean <dominique.bej...@eolya.fr> > wrote: > > Hi, > > Thank you all for your responses. I will try to answer your questions in > one single message. > > We are starting to investigate performance issues with a new customer. > There are several bad practices (commit, sharding, replicas count and > types, heap size, ...), that can explain these issues and we will work on > it in the next few days. I agree we need to better understand specific > usage and make some tests after fixing the bad practices. > > Anyway, one of the specific aspects is these huge servers, so I am trying > to see what is the best way to use all these ressources. > > > * Why do you want to split it up at all? > > Because one of the bad practices is a huge heap size (80 Gb). I am pretty > sure this heap size is not required and anyway it doesn't respect the 31Gb > limit. After determining the best heap size, if this size is near 31Gb, I > imagine it is better to have several Solr JVMs with less heap size. For > instance 2 Solr JVMs with 20 Gb each or 4 Solr JVMs with 10 Gb each. > > According to Walter's response and Mattew's question, that doesn't seem > like a good idea. > > > * MMapDirectory JVM sharing > > This point is the main reason for my message. If several Solr JVMs are > running on one server, will MMapDirectory work fine or will the JVMs fight > with each other in order to use off heap memory ? > > According to Shawn's response it should work fine. > > > What would the iops look like? > > Not monitored yet. > Storage configuration is the second point that I would like to investigate > in order to better share disk resources. > Instead have one single RAID 6 volume, isn't it better to have one distinct > not RAID volume per Solr node (if multiple Solr nodes are running on the > server) or multiple not RAID volumes use by a single Solr JVM (if only one > Solr node is running on the server) ? > > I note the various suggestions in your answers (ZFS, RAID 10, ...) > > Thank you Dima and Shawn > > > Regards > > Dominique > > Le jeu. 6 oct. 2022 à 09:57, Dominique Bejean <dominique.bej...@eolya.fr> a > écrit : > >> Hi, >> >> One of our customer have huge servers >> >> - Bar-metal >> - 64 CPU >> - 512 Gb RAM >> - 6x2Tb disk in RAID 6 (so 2Tb disk space available) >> >> >> I think the best way to optimize resources usage of these servers is to >> install several Solr instances. >> >> I imagine 2 scenarios to be tested according to data volumes, update rate, >> request volume, ... >> >> Do not configure disks in RAID 6 but, leave 6 standard volumes (more space >> disk, more I/O available) >> Install 3 or 6 solr instances each one using 1 ou 2 disk volumes >> >> Obviously, replicate shards and verify replicates of a shard are not >> located on the same physical server. >> >> What I am not sure is how MMapDirectory will work with several Solr >> instances. Will off heap memory correctly managed and shared between >> several Solr instances ? >> >> Thank you for your advice. >> >> Dominique >> >> >> >> >>
