Bringing together the Apache Cassandra experts from the community and DataStax.

Want to learn? Have a question? Want to share your expertise? You are in the right place!

Not sure where to begin? Getting Started

 

question

dmngaya avatar image
dmngaya asked Erick Ramirez answered

Why do you recommend both -Xms and -Xmx flags be the same size ?

Why do you recommand both -Xms and -Xmx flags in the same size ? is it recommendation for dse 6.8 ?

cassandratuning
10 |1000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 1.0 MiB each and 10.0 MiB total.

1 Answer

Erick Ramirez avatar image
Erick Ramirez answered

@dmngaya There are 2 benefits for explicitly setting the minimum heap size (-Xms) to be the same as the max size (-Xmx):

  1. Setting the same value prevents stop-the-world GC pauses when the heap gets resized.
  2. Setting the minimum size pre-allocates the required RAM on startup and locks the heap in memory reducing the chances of the JVM getting swapped out.

Cheers!

Share
10 |1000 characters needed characters left characters exceeded

Up to 8 attachments (including images) can be used with a maximum of 1.0 MiB each and 10.0 MiB total.