their respective _OPT variable. # There is no default; the JVM will autoscale based upon machine # memory size. # export HADOOP_HEAPSIZE_MAX= # The minimum amount of heap to use (Java -Xms). If no unit their respective _OPT variable. # There is no default; the JVM will autoscale based upon machine # memory size. # export HADOOP_HEAPSIZE_MIN= HADOOP_NAMENODE_OPTS=-Xmx102400m （2）查看 NameNode 占用内存 这里我们发现所有的文件块都是存储在 DISK，按照理论一个副本存储在 RAM_DISK， 其他副本存储在 DISK 中，这是因为，我们还需要配置“dfs.datanode.max.locked.memory”， “dfs.block.size”参数。 那么出现存储策略为 LAZY_PERSIST 时，文件块副本都存储在 DISK 上的原因有如下两 点： （1）当客户端所在的 DataNode

about a dog and cat, but we know that they are both cute, have been domesticated for a while and are safe. These two animals are more similar to each other than to a random animal like a chimp. Similarly bear, if we ever accidentally cross paths. We build an associative memory when about them over our lifetime. This associative memory helps us visualize the similarities or differences between a pair of extremely dangerous, even though stuffed teddy bears have conditioned us into thinking that they might be safe and cute. A raccoon can seem to be cute (remember Rocket the raccoon from Guardians of the Galaxy

. . . . . . . . . . . . . . . . . . . . . 74 4.8 Memory overcommitment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 4.8.1 Memory ballooning . . . . . . . . . . . . . . . . . . . . VirtualBox Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 9.22.1 Memory ballooning control . . . . . . . . . . . . . . . . . . . . . . . . . 174 9.22.2 Host isolation detection . . . . 205 12.8.1 Cannot start VM, not enough contiguous memory . . . . . . . . . . . . 205 7 Contents 12.8.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . . . . 205 13 Security

. . . . . . . . . . . . . . . . . . . . . 74 4.8 Memory overcommitment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 4.8.1 Memory ballooning . . . . . . . . . . . . . . . . . . . . VirtualBox Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175 9.22.1 Memory ballooning control . . . . . . . . . . . . . . . . . . . . . . . . . 175 9.22.2 Host isolation detection . . . . 206 12.8.1 Cannot start VM, not enough contiguous memory . . . . . . . . . . . . 206 7 Contents 12.8.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . . . . 206 13 Security

. . . . . . . . . . . . . . . . . . . . . 74 4.8 Memory overcommitment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 4.8.1 Memory ballooning . . . . . . . . . . . . . . . . . . . . VirtualBox Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 174 9.22.1 Memory ballooning control . . . . . . . . . . . . . . . . . . . . . . . . . 174 9.22.2 Host isolation detection . . . . 205 12.8.1 Cannot start VM, not enough contiguous memory . . . . . . . . . . . . 205 7 Contents 12.8.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . . . . 205 13 Security

. . . . . . . . . . . . . . . . . . . . . 77 4.8 Memory overcommitment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 4.8.1 Memory ballooning . . . . . . . . . . . . . . . . . . . . VirtualBox Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 9.21.1 Memory ballooning control . . . . . . . . . . . . . . . . . . . . . . . . . 191 9.21.2 Host isolation detection . . . . . . . 224 12.8.1 Cannot start VM, not enough contiguous memory . . . . . . . . . . . . 224 12.8.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . . . . 224 13 Security guide

. . . . . . . . . . . . . . . . . . . . . 77 4.8 Memory overcommitment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 4.8.1 Memory ballooning . . . . . . . . . . . . . . . . . . . . VirtualBox Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191 9.21.1 Memory ballooning control . . . . . . . . . . . . . . . . . . . . . . . . . 191 9.21.2 Host isolation detection . . . . . . . 224 12.8.1 Cannot start VM, not enough contiguous memory . . . . . . . . . . . . 224 12.8.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . . . . 224 13 Security guide

. . . . . . . . . . . . . . . . . . . . . 77 4.8 Memory overcommitment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77 4.8.1 Memory ballooning . . . . . . . . . . . . . . . . . . . . VirtualBox Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190 9.21.1 Memory ballooning control . . . . . . . . . . . . . . . . . . . . . . . . . 191 9.21.2 Host isolation detection . . . . . . . 223 12.8.1 Cannot start VM, not enough contiguous memory . . . . . . . . . . . . 223 12.8.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . . . . 223 13 Security guide

. . . . . . . . . . . . . . . . . . . . . 72 4.8 Memory overcommitment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 4.8.1 Memory ballooning . . . . . . . . . . . . . . . . . . . . 163 9.19.3 Mac OS X: starting the webservice via launchd . . . . . . . . . . . . . . 164 9.20 Memory Ballooning Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 164 10 Technical background . . . . . . . 191 12.7.1 Cannot start VM, not enough contiguous memory . . . . . . . . . . . . 191 12.7.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . . . . 191 13 Security guide

. . . . . . . . . . . . . . . . . . . . . 76 4.8 Memory overcommitment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 4.8.1 Memory ballooning . . . . . . . . . . . . . . . . . . . . VirtualBox Watchdog . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182 9.22.1 Memory ballooning control . . . . . . . . . . . . . . . . . . . . . . . . . 182 9.22.2 Host isolation detection . . . . . . . 214 12.8.1 Cannot start VM, not enough contiguous memory . . . . . . . . . . . . 214 12.8.2 VM aborts with out of memory errors on Solaris 10 hosts . . . . . . . . 214 13 Security guide