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标题: IBM Power Systems 上的 MongoDB 调优指南（2） [打印本页]

作者: look_w 时间: 2017-12-8 09:07 标题: IBM Power Systems 上的 MongoDB 调优指南（2）

如果来宾需要多于 10 个核心和约 100GB 内存，那么来宾应使用两个节点。在下面的 libvirt XML 定义示例中，使用了节点 16 和 17 来限制来宾。

...
<memory unit='KiB'>125566976</memory>
  <currentMemory unit='KiB'>125566976</currentMemory>
  <memoryBacking>
<hugepages/>
  </memoryBacking>
  <vcpu placement='static'>80</vcpu>
  <cputune>
<vcpupin vcpu='0' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='1' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='2' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='3' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='4' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='5' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='6' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='7' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='8' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='9' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='10' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='11' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='12' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='13' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='14' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='15' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='16' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='17' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='18' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='19' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='20' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='21' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='22' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='23' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='24' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='25' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='26' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='27' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='28' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='29' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='30' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='31' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='32' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='33' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='34' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='35' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='36' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='37' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='38' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='39' cpuset='80,88,96,104,112'/>
<vcpupin vcpu='40' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='41' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='42' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='43' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='44' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='45' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='46' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='47' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='48' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='49' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='50' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='51' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='52' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='53' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='54' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='55' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='56' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='57' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='58' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='59' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='60' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='61' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='62' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='63' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='64' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='65' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='66' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='67' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='68' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='69' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='70' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='71' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='72' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='73' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='74' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='75' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='76' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='77' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='78' cpuset='120,128,136,144,152'/>
<vcpupin vcpu='79' cpuset='120,128,136,144,152'/>
  </cputune>
……

<numa>
   <cell cpus='0-39' memory='62783488'/>
   <cell cpus='40-79' memory='62783488'/>
  </numa>

...

在来宾使用大页面时，向主机上的节点 16 和 17 分配足够多的大页面：
echo 3840 >/sys/devices/system/node/node16/hugepages/hugepages-16384kB/nr_hugepages

echo 3840 >/sys/devices/system/node/node17/hugepages/hugepages-16384kB/nr_hugepages

使用 pagemapscan-numa 实用程序，确保来宾限制在节点 16 和 17 中，如下所示：

./pagemapscan-numa 85538 2

               host-node00 host-node01 host-node16 host-node17 not-present
               ----------- ----------- ----------- ----------- -----------
VM-node00|       0(000%)       0(000%) 978176(100%)       0(000%)       0(000%)
VM-node01|       0(000%)       0(000%)             0(000%) 978176(100%)       0(000%)

在 PowerKVM 3.1 中，libvirt XML 定义有一个新的内存固定选项，该选项不需要使用大页面来在来宾上设置内存关联。

新 numatune memnode 特性可将来宾节点 cellid（与它上方的单元创建节匹配）映射到相应的主机节点 nodeset。下面的代码示例显示了定义的第一个单元创建部分：

大页面支持在使用基于 Java™ 的 MongoDB 应用程序时，只需要在来宾上配置大页面支持。

libvirt XML 定义文件中的来宾定义必须按以下方式指定 memoryBacking：

<domain type=’kvm’>
<name>myguest<\name>
<uuid>...</uuid>
<memory>2048</memory>
<currentMemory>2048</currentMemory>
<memoryBacking>
<hugepages/>
</memoryBacking>
...
</domain>

运营以下命令在来宾中启用大页面：echo 2000 > /proc/sys/vm/nr_hugepages
hugeadm --create-mounts
您还需要根据后面的 Application-level -> Java Tuning 部分的介绍，在主机上分配大内存。

数据磁盘直通因为来宾分区上的虚拟 SCSI (VSCSI) 模拟磁盘通常很慢，所以您应在 libvirt XML 定义文件中将磁盘设置为 lun，如下所示：

有关更多信息，请参阅 IBM Redbooks 中的第 98 页。
网络 PCI 直通在 libvirt XML 定义中将 type 属性设置为 pci，如下面的示例所示：
<devices>
...
<hostdev mode=’subsystem’ type=’pci’ managed=’yes’>
<source>
<address domain=’0x000’ bus=’0x15’ slot=’0x00’ function=’0x0’/>
</source>
</hostdev>
</devices>

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