Loading... <!-- wp:paragraph --> <p>很多用户在部署VXRAIL超融合后发现,ESXI主机节点内存占用较高。普遍ESXI Host占用超过30G</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>如图所示的节点配置为:</strong></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>VxRail V570F, All Flash 384G内存 </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>磁盘组构成</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>Cache缓存</strong>: 1*800G MU SSD </p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><strong>数据</strong>:2*1.92T RI SSD</p> <!-- /wp:paragraph --> <!-- wp:image {"id":1975,"sizeSlug":"large","linkDestination":"none"} --> <figure class="wp-block-image size-large"><img src="https://www.crazycen.com/usr/uploads/2021/08/image-1024x290.png" alt="" class="wp-image-1975" style=""></figure> <!-- /wp:image --> <!-- wp:paragraph --> <p>vSAN内存消耗,官方有明确的计算公式</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>vSANFootprint = HOST_FOOTPRINT + NumDiskGroups * DiskGroupFootprint</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>DiskGroupFootprint = DISKGROUP_FIXED_FOOTPRINT + DISKGROUP_SCALABLE_FOOTPRINT + CacheSize * CACHE_DISK_FOOTPRINT + NumCapacityDisks * CAPACITY_DISK_FOOTPRINT</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>HOST_FOOTPRINT:每个 ESXi 主机的 vSAN 消耗的固定内存量(不管磁盘组为何)<br>NumDiskGroups:主机中的磁盘组数。(范围 1-5)<br>DiskGroupFootprint:分配给主机中每个单独磁盘组的内存量。<br>NumCapacityDisks:每个磁盘组中的容量磁盘数。<br>CAPACITY_DISK_FOOTPRINT:每个容量磁盘分配的内存量(无论磁盘大小如何)。<br>DISKGROUP_FIXED_FOOTPRINT:分配给主机中每个单独磁盘组的固定内存量。<br>DISKGROUP_SCALABLE_FOOTPRINT:根据 ESXi 主机的物理内存量分配给每个单独磁盘组的内存量<br>CacheSize:缓存磁盘大小,以 GB 为单位(对于 SSD,范围为 0-600;对于混合配置,范围为 0-2 TB)<br>CACHE_DISK_FOOTPRINT:每 GB 缓存磁盘分配的内存量。</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>对于以上参数,部分参数具有常量数值</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>All-Flash</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>HOST_FOOTPRINT = 8620 MB</li><li>CAPACITY_DISK_FOOTPRINT = 240 MB (ALL_FLASH)</li><li>CACHE_DISK_FOOTPRINT = 15 MB (ALL_FLASH)</li><li>DISKGROUP_FIXED_FOOTPRINT = 8420 MB (ALL_FLASH) *</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p>Hybrid</p> <!-- /wp:paragraph --> <!-- wp:list --> <ul><li>CAPACITY_DISK_FOOTPRINT = 300 MB (HYBRID)</li><li>CACHE_DISK_FOOTPRINT = 10 MB (HYBRID)</li><li>DISKGROUP_FIXED_FOOTPRINT = 7840 MB (HYBRID)</li><li>DISKGROUP_SCALABLE_FOOTPRINT = 0.5% of system memory **</li></ul> <!-- /wp:list --> <!-- wp:paragraph --> <p><strong>注意</strong>:对于启用仅压缩功能的磁盘组,每个容量磁盘需付出 39.5 MB 的额外成本。<br>对于启用去重功能的磁盘组,每个磁盘组需付出 120 MB 的额外成本。<br>对于混合配置,可扩展的占用空间将是系统内存的 0.5% 或缓存磁盘大小的 0.2%(以较小者为准)。<br><br>全闪存的缓存磁盘上限为 600 GB,因此,使用大于 600 GB 的 SSD 将不会消耗额外的内存。<br><br>该公式假设使用的是同构磁盘组,即磁盘的数量和大小在主机的磁盘组之间相同。对于异构磁盘组,必须单独计算并汇总每个磁盘组的 DiskGroupFootprint。</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>对于刚刚的配置实例,我们可以计算</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>公式:<br>HOST_FOOTPRINT + ( NumDiskGroups * ( DISKGROUP_FIXED_FOOTPRINT + DISKGROUP_SCALABLE_FOOTPRINT + ( CacheSize * CACHE_DISK_FOOTPRINT) + NumCapacityDisks * CAPACITY_DISK_FOOTPRINT))</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>计算结果8610+(8420+0.5%*384*1024+600*15+2*240)=28476.08MB</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>当前配置的VSAN的整个开销在28G,还应当考虑esxi主机的正常开销。</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>参考文档:</p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p><span class="external-link"><a class="no-external-link" href="https://kb.vmware.com/s/article/2113954?lang=en_us" target="_blank"><i data-feather="external-link"></i>Understanding vSAN memory consumption in ESXi 6.x and 7.x</a></span></p> <!-- /wp:paragraph --> <!-- wp:paragraph --> <p>注意:文档中英文数值不一致</p> <!-- /wp:paragraph --> Last modification:October 6, 2023 © Allow specification reprint Support Appreciate the author AliPayWeChat Like 如果觉得我的文章对你有用,请随意赞赏