> I know that Cassandra is built for scale out on commodity hardware The term "commodity hardware" is not very useful, though the averageserver-class machine bought in 2017 can work.
Netflix found that SSD helped greatly with compactions in production.Generally servers use 10 GB networking in 2017. 128 GB is commonly used, but I would use 256+ GB in new servers. I don't recommend the Cassandra JBOD configuration since losingone drive means rebuilding the node immediately, which manyorganizations aren't responsive enough to do. Thanks, James. -- Cassandra/MySQL DBA. Available in San Jose area or remote. cass_top: https://github.com/jamesbriggs/cassandra-top From: "Steinmaurer, Thomas" <thomas.steinmau...@dynatrace.com> To: "user@cassandra.apache.org" <user@cassandra.apache.org> Sent: Friday, November 3, 2017 6:34 AM Subject: cassandra.yaml configuration for large machines (scale up vs. scale out) <!--#yiv9147268810 _filtered #yiv9147268810 {font-family:Wingdings;panose-1:5 0 0 0 0 0 0 0 0 0;} _filtered #yiv9147268810 {font-family:"Cambria Math";panose-1:2 4 5 3 5 4 6 3 2 4;} _filtered #yiv9147268810 {font-family:Calibri;panose-1:2 15 5 2 2 2 4 3 2 4;}#yiv9147268810 #yiv9147268810 p.yiv9147268810MsoNormal, #yiv9147268810 li.yiv9147268810MsoNormal, #yiv9147268810 div.yiv9147268810MsoNormal {margin:0cm;margin-bottom:.0001pt;font-size:11.0pt;font-family:"Calibri", sans-serif;}#yiv9147268810 a:link, #yiv9147268810 span.yiv9147268810MsoHyperlink {color:#0563C1;text-decoration:underline;}#yiv9147268810 a:visited, #yiv9147268810 span.yiv9147268810MsoHyperlinkFollowed {color:#954F72;text-decoration:underline;}#yiv9147268810 p.yiv9147268810MsoListParagraph, #yiv9147268810 li.yiv9147268810MsoListParagraph, #yiv9147268810 div.yiv9147268810MsoListParagraph {margin-top:0cm;margin-right:0cm;margin-bottom:0cm;margin-left:36.0pt;margin-bottom:.0001pt;font-size:11.0pt;font-family:"Calibri", sans-serif;}#yiv9147268810 span.yiv9147268810EmailStyle17 {font-family:"Calibri", sans-serif;color:windowtext;}#yiv9147268810 .yiv9147268810MsoChpDefault {} _filtered #yiv9147268810 {margin:70.85pt 70.85pt 2.0cm 70.85pt;}#yiv9147268810 div.yiv9147268810WordSection1 {}#yiv9147268810 _filtered #yiv9147268810 {} _filtered #yiv9147268810 {font-family:Symbol;} _filtered #yiv9147268810 {font-family:"Courier New";} _filtered #yiv9147268810 {font-family:Wingdings;} _filtered #yiv9147268810 {font-family:Symbol;} _filtered #yiv9147268810 {font-family:"Courier New";} _filtered #yiv9147268810 {font-family:Wingdings;} _filtered #yiv9147268810 {font-family:Symbol;} _filtered #yiv9147268810 {font-family:"Courier New";} _filtered #yiv9147268810 {font-family:Wingdings;}#yiv9147268810 ol {margin-bottom:0cm;}#yiv9147268810 ul {margin-bottom:0cm;}-->Hello, I know that Cassandra is built for scale out on commodity hardware, but I wonder if anyone can share some experience when running Cassandra on rather capable machines. Let’s say we have a 3 node cluster with 128G RAM, 32 physical cores (16 per CPU socket), Large Raid with Spinning Disks (so somewhere beyond 2000 IOPS). What are some recommended cassandra.yaml configuration / JVM settings, e.g. we have been using with something like that as a first baseline: · 31G heap, G1, -XX:MaxGCPauseMillis=2000 · concurrent_compactors: 8 · compaction_throughput_mb_per_sec: 128 · key_cache_size_in_mb: 2048 · concurrent_reads: 256 · concurrent_writes: 256 · native_transport_max_threads: 256 Anything else we should add to our first baseline of settings? E.g. although we have a key cache of 2G, nodetool info gives me only 0.451 as hit rate: Key Cache : entries 2919619, size 1.99 GB, capacity 2 GB, 71493172 hits, 158411217 requests, 0.451 recent hit rate, 14400 save period in seconds Thanks, Thomas The contents of this e-mail are intended for the named addressee only. It contains information that may be confidential. Unless you are the named addressee or an authorized designee, you may not copy or use it, or disclose it to anyone else. If you received it in error please notify us immediately and then destroy it. Dynatrace Austria GmbH (registration number FN 91482h) is a company registered in Linz whose registered office is at 4040 Linz, Austria, Freistädterstraße 313
