G1 GC for 100GB+ heaps

[Kees Jan Koster]

Dear All,

Marcus Lagergren suggested I post this here.

Sorry if this message goes through twice, I had some trouble posting.

We are considering switching to G1 GC for a decently-sized HBase cluster. We run an HBase cluster on the bare metal with 128GB RAM in each machine. Today we use Java 7 with CMS, but we’d like to switch to Java 8 with G1.

* Are there practical limits to the heap size that we can use with G1 can have? Can we just allocate 100GB+ heaps and expect G1 to work untuned?

* Does the G1 GC have failure modes for edge cases that we need to keep in mind?

* What about region size? Should we keep some form of relation between the size of the HBase blocks and the G1 region size?

* What tunables do we have to look at and learn more about when we want to run with this size heap?

* Any gotcha’s or best practices to keep in mind when we switch over to G1?

--
Kees Jan

http://java-monitor.com/
kjkoster at kjkoster.org
+31651838192

Human beings make life so interesting. Do you know that in a universe so full of wonders,
they have managed to invent boredom. Quite astonishing... -- Terry Pratchett