我有一个由4个节点组成的集群,每个节点都有16核CPU和100GB RAM(每个机箱上有2个节点)。
目前,所有节点都使用Cassandra(v2.1.4)的默认JVM设置在运行。使用此设置,每个节点使用13GB RAM和30% CPU。这是一个写入较多的集群,偶尔会进行删除或更新操作。
我需要调整Cassandra的JVM设置以利用更多内存吗?我应该关注哪些方面来做出适当的设置?
我有一个由4个节点组成的集群,每个节点都有16核CPU和100GB RAM(每个机箱上有2个节点)。
目前,所有节点都使用Cassandra(v2.1.4)的默认JVM设置在运行。使用此设置,每个节点使用13GB RAM和30% CPU。这是一个写入较多的集群,偶尔会进行删除或更新操作。
我需要调整Cassandra的JVM设置以利用更多内存吗?我应该关注哪些方面来做出适当的设置?
如果您的机器配备了100GB RAM(如果您确实在使用“默认JVM设置”),则JVM的最大堆大小应该被限制在8192M。实际上,除非您遇到垃圾回收方面的问题,否则我不会偏离这个值。
Cassandra的JVM资源可以在文件中进行设置。如果您感兴趣,请查看代码,并查找方法。这应该能让您了解Cassandra如何计算默认的JVM设置。
我需要考虑哪些因素来进行适当的设置?
如果您正在运行OpsCenter(您应该这样做),请添加一个“Heap Used”和“Non Heap Used”的图表。
#!/bin/bash
clear
echo "This is how Cassandra will determine its default Heap and GC Generation sizes."
system_memory_in_mb=`free -m | awk '/Mem:/ {print $2}'`
half_system_memory_in_mb=`expr $system_memory_in_mb / 2`
quarter_system_memory_in_mb=`expr $half_system_memory_in_mb / 2`
echo " memory = $system_memory_in_mb"
echo " half = $half_system_memory_in_mb"
echo " quarter = $quarter_system_memory_in_mb"
echo "cpu cores = "`egrep -c 'processor([[:space:]]+):.*' /proc/cpuinfo`
#cassandra-env logic duped here
#this should help you to see how much memory is being allocated
#to the JVM
if [ "$half_system_memory_in_mb" -gt "1024" ]
then
half_system_memory_in_mb="1024"
fi
if [ "$quarter_system_memory_in_mb" -gt "8192" ]
then
quarter_system_memory_in_mb="8192"
fi
if [ "$half_system_memory_in_mb" -gt "$quarter_system_memory_in_mb" ]
then
max_heap_size_in_mb="$half_system_memory_in_mb"
else
max_heap_size_in_mb="$quarter_system_memory_in_mb"
fi
MAX_HEAP_SIZE="${max_heap_size_in_mb}M"
# Young gen: min(max_sensible_per_modern_cpu_core * num_cores, 1/4 * heap size)
max_sensible_yg_per_core_in_mb="100"
max_sensible_yg_in_mb=`expr ($max_sensible_yg_per_core_in_mb * $system_cpu_cores)`
desired_yg_in_mb=`expr $max_heap_size_in_mb / 4`
if [ "$desired_yg_in_mb" -gt "$max_sensible_yg_in_mb" ]
then
HEAP_NEWSIZE="${max_sensible_yg_in_mb}M"
else
HEAP_NEWSIZE="${desired_yg_in_mb}M"
fi
echo "Max heap size = " $MAX_HEAP_SIZE
echo " New gen size = " $HEAP_NEWSIZE
更新于20160212:
另外,请务必查看Amy Tobey的2.1 Cassandra调整指南。她有一些关于如何使您的集群运行得更加优化的极好的建议。
system_cpu_cores未正确设置。编辑正确的设置以执行。
#!/bin/bash
clear
echo "This is how Cassandra will determine its default Heap and GC Generation sizes."
system_memory_in_mb=`free -m | awk '/Mem:/ {print $2}'`
half_system_memory_in_mb=`expr $system_memory_in_mb / 2`
quarter_system_memory_in_mb=`expr $half_system_memory_in_mb / 2`
system_cpu_cores=`cat /proc/cpuinfo | grep -i processor | wc -l`
echo " memory = $system_memory_in_mb"
echo " half = $half_system_memory_in_mb"
echo " quarter = $quarter_system_memory_in_mb"
echo "cpu cores = `egrep -c 'processor([[:space:]]+):.*' /proc/cpuinfo`"
#cassandra-env logic duped here
#this should help you to see how much memory is being allocated
#to the JVM
if [ "$half_system_memory_in_mb" -gt "1024" ]
then
half_system_memory_in_mb="1024"
fi
if [ "$quarter_system_memory_in_mb" -gt "8192" ]
then
quarter_system_memory_in_mb="8192"
fi
if [ "$half_system_memory_in_mb" -gt "$quarter_system_memory_in_mb" ]
then
max_heap_size_in_mb="$half_system_memory_in_mb"
else
max_heap_size_in_mb="$quarter_system_memory_in_mb"
fi
MAX_HEAP_SIZE="${max_heap_size_in_mb}M"
# Young gen: min(max_sensible_per_modern_cpu_core * num_cores, 1/4 * heap size)
max_sensible_yg_per_core_in_mb="100"
max_sensible_yg_in_mb=`expr $max_sensible_yg_per_core_in_mb * $system_cpu_cores`
desired_yg_in_mb=`expr $max_heap_size_in_mb / 4`
if [ "$desired_yg_in_mb" -gt "$max_sensible_yg_in_mb" ]
then
HEAP_NEWSIZE="${max_sensible_yg_in_mb}M"
else
HEAP_NEWSIZE="${desired_yg_in_mb}M"
fi
echo "Max heap size = " $MAX_HEAP_SIZE
echo " New gen size = " $HEAP_NEWSIZE