Cassandra列系列大于节点驱动器空间 [英] Cassandra column family bigger than nodes drive space

问题描述

我想启动一个Cassandra集群（例如3个节点），并且我的应用程序只有一个列族。

阅读文档后，我了解了cassandra如何在多个节点之间复制一个列族。

例如。每个节点都有2Tb的驱动器空间，并且在每个节点上复制列族，因此每个节点都包含它的完整副本。

如果几年后列族超过2Tb，我没有增加驱动器空间的可能性吗？

如果我要添加更多的10个节点，我希望将该列族拆分为多个部分并存储在不同的驱动器中在节点上，因此它可以增加到无限大。如果我理解正确，列族仅限于群集中的最小驱动器空间吗？

解决方案

您所描述的方案仅对于所有数据都复制到所有节点的情况。您可以通过将复制因子（RF）设置为节点数来配置它。

但是，RF可以小于节点数，并且不需要扩展例如，如果您现在有3个RF 3的节点，则每个节点将包含所有数据的副本，就像您所说的那样。

但是，如果再添​​加3个节点并将RF保持在3，则每个节点将拥有一半的数据。您可以继续添加更多的节点，以便每个节点包含越来越少的数据。

因此，原则上对数据的大小没有限制。 / p>

I want to start a cassandra cluster (eg. 3 nodes), and my application has only one column family.

After reading documentation, I understood how cassandra replicates one column family across multiple nodes.

For eg. every node has 2Tb drive space and column family is replicated on every node so every node contains a full copy of it.

What happens if after some years that column family will exceed 2Tb and I do not have posibility to increase drive space?

If I will add more 10 nodes, I want that column family to be splitted into parts and stored on different drives on nodes, so it can increase to infinite size. If I understood correctly, a column family is limited to the smallest drive space in the cluster?

解决方案

The scenario you describe is only for the case when all data is replicated to all nodes. You configure this by setting replication factor (RF) to be the number of nodes.

However, the RF can be less than the number of nodes and does not need to scale if you add more nodes.

For example, if you today had 3 nodes with RF 3, each node will contain a copy of all the data, as you say. But then if you add 3 more nodes and keep RF at 3, each node will have half the data. You can keep adding more nodes so each node contains a smaller and smaller proportion of the data.

Therefore there is no limit in principle to how big your data can be.

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