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图像管理的棱镜中心限制

  • 2021年6月25日
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我需要一些帮助来理解棱镜中心图像管理。当我读到棱镜中心指南(限制)我不明白“在复制操作期间,集群A变得不可用。”

棱镜中心指南中的这条评论意味着不能使用“集群A”棱镜元素?这也意味着所有的操作都像“集群A”中的虚拟机发放操作一样暂停?

我想知道副作用和确切的行为是发生使用“集群A”时变得不可用。请帮助我。

谢谢您的帮助:)

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最佳答案Nupur。Sakhalkar2021年7月7日17:48

@hoseong<\/user-mention>\u00a0I believe you are referring to the following section mentioned in the PC Image Management Limitations<\/a> guide:<\/p>
Prism Central can take up to 15 minutes to switch the image propagation from an alternative cluster. For example, if an image is located on clusters A and B. As a result of an image placement policy you applied to that image, cluster A starts copying the image to cluster C. During the copy operation, cluster A becomes unavailable. In such a case, Prism Central takes up to 15 minutes to switch to cluster B and start copying the image from cluster B to cluster C.<\/code><\/pre>

\u00a0The above section is giving an example for the image placement policy workflow. It is simply stating that let\u2019s suppose if you originally uploaded an image using Prism Central to cluster A and cluster B, so currently only these two clusters (A & B) will have this image available in it. Now, in scenarios where you need to use this image ( originally uploaded on cluster A & B) on a different cluster C, then you can do so using the image placement policy.<\/p>

In this case, when you try to get this image on cluster C, Prism Central will select any one cluster which originally had the image (for e.g. cluster A) and then will copy it to the cluster C so that cluster C can use this image.<\/p>

However, in scenarios where when this image is getting copied over to cluster C, cluster A went offline\/down\u00a0due to some issues (for e..g power outage in DC, network issues, etc.) , then Prism Central (PC)\u00a0will switch the image\u00a0to copy from cluster B (instead of cluster A since cluster A went down) to cluster C. This switch can take up to 15 minutes to happen - that is what is mentioned in the above example given in the guide.\u00a0<\/p>

This doesn\u2019t mean that when the image is being copied from cluster A to cluster C, cluster A will be down\/unavailable. Cluster A stays up\/is available for normal use even during when the image is being copied over to cluster C. The above snippet was more of a hypothetical scenario to explain what PC will do in case if cluster A goes down during the image copy operation to cluster C.\u00a0
\u00a0<\/p>

I hope that clears that your confusion about the image copy statement mentioned in the guide. Kindly let me know if you have any more questions about this one!<\/p>","className":"post__content__best_answer"}">

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@hoseong我相信你指的是《PC镜像管理限制导游:

棱镜中心可以花15分钟从另一个集群切换图像传播。例如,如果一个映像位于集群A和b上。由于您对该映像应用了一个映像放置策略,因此集群A开始将该映像复制到集群c。在复制操作期间,集群A将不可用。在这种情况下,Prism Central需要15分钟的时间切换到集群B,并开始将图像从集群B复制到集群C。

上一节给出了一个图像放置策略工作流的示例。它只是简单地说明,让我们假设,如果您最初使用Prism Central上传了一张图片到集群A和集群B,所以目前只有这两个集群(A和B)将有这个图像在它。现在,如果您需要在不同的集群C上使用该图像(最初上传在集群A和B上),那么您可以使用图像放置策略。

在这种情况下,当你尝试在C类上获取这张图片时,Prism Central将选择任何一个原来拥有这张图片的类(例如A类),然后将其复制到C类中,以便C类可以使用这张图片。

然而,当这个映像被复制到集群C时,集群A由于一些问题(例如直流断电、网络问题等)而离线/停机,然后Prism Central (PC)将切换图像从集群B(而不是集群A,因为集群A下降)复制到集群c。这种切换可能需要15分钟——这是在指南中给出的上面的例子中提到的。

这并不意味着当映像从集群A复制到集群C时,集群A将关闭/不可用。集群A保持正常运行/即使在映像被复制到集群C时也可以正常使用。上面的代码片段更像是一个假设的场景,用来解释如果集群A在映像复制到集群C时出现故障,PC将会做什么。

我希望这能澄清您对指南中提到的图像复制声明的困惑。如果你有更多关于这个的问题,请让我知道!

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