Enable async GC logging for JDK versions which support it to avoid potential hiccups caused by GC log file I/O blocking

patch by Dmitry Konstantinov; reviewed by Stefan Miklosovic for CASSANDRA-21372

CHANGES.txt

@@ -1,4 +1,5 @@
 6.0-alpha2
+ * Enable async GC logging for JDK versions which support it to avoid potential hiccups caused by GC log file I/O blocking (CASSANDRA-21372)
  * Add rowsMutatedPerWriteHistogram metric to track rows mutated per write request (CASSANDRA-21320)
  * Add TotalRowsRead and TotalRowsMutated counters to TableMetrics for accurate per-table row throughput tracking (CASSANDRA-21321)
  * Move exception handling of SPI startup checks when iterating over them (CASSANDRA-21409)

conf/jvm17-server.options

@@ -91,6 +91,12 @@
 --add-opens java.base/java.nio=ALL-UNNAMED
 
 ### GC logging options -- uncomment to enable
+-Xlog:async
+
+# In async mode JVM writes logs into a circular memory buffer; if the buffer fills up
+# before it is drained, log records are silently dropped
+# the default buffer size can be adjusted using the next option if needed
+# -XX:AsyncLogBufferSize=2m
 
 # Java 11 (and newer) GC logging options:
 # See description of https://bugs.openjdk.java.net/browse/JDK-8046148 for details about the syntax

conf/jvm21-server.options

@@ -111,6 +111,12 @@
 
 
 ### GC logging options -- uncomment to enable
+-Xlog:async
+
+# In async mode JVM writes logs into a circular memory buffer; if the buffer fills up
+# before it is drained, log records are silently dropped
+# the default buffer size can be adjusted using the next option if needed
+# -XX:AsyncLogBufferSize=2m
 
 # Java 11 (and newer) GC logging options:
 # See description of https://bugs.openjdk.java.net/browse/JDK-8046148 for details about the syntax