There are two factors: 1> the raw number of replicas on a Solr node. 2> total resources Solr needs.
You say “..it’s unstalble…”. _How_ is it unstable? What symptoms are you seeing? You might want to review: https://cwiki.apache.org/confluence/display/solr/UsingMailingLists And not as you add more cores, you put more pressure on memory, I/O, etc. So whether it’s the raw number of cores or you’re just exhausting memory, overloading your CPU, etc. is hard to say without more information. Best, Erick > On Aug 29, 2019, at 1:31 AM, Hendrik Haddorp <hendrik.hadd...@gmx.net> wrote: > > Hi, > > we are usually using Solr Clouds with 5 nodes and up to 2000 collections > and a replication factor of 2. So we have close to 1000 cores per node. > That is on Solr 7.6 but I believe 7.3 worked as well. We tuned a few > caches down to a minimum as otherwise the memory usage goes up a lot. > The Solr UI is having some problems with a high number of collections, > like lots of timeouts when loading the status. > > Older Solr versions had problem with the overseer queue in ZooKeeper. If > you restarted too many nodes at once then the queue got too long and > Solr died and required some help and cleanup to start at all again. > > regards, > Hendrik > > On 29.08.19 05:27, Hongxu Ma wrote: >> Hi >> I have a solr-cloud cluster, but it's unstable when collection number is >> big: 1000 replica/core per solr node. >> >> To solve this issue, I have read the performance guide: >> https://cwiki.apache.org/confluence/display/SOLR/SolrPerformanceProblems >> >> I noted there is a sentence on solr-cloud section: >> "Recent Solr versions perform well with thousands of replicas." >> >> I want to know does it mean a single solr node can handle thousands of >> replicas? or a solr cluster can (if so, what's the size of the cluster?) >> >> My solr version is 7.3.1 and 6.6.2 (looks they are the same in performance) >> >> Thanks for you help. >> >> >
