The disk usage metric shows the percentage of space used on the data partition of a node. This includes the main Cassandra files containing your data as well as working files such as snapshots for backups and temporary copies of files used for compactions.
We recommend that disk usage is kept to less than 70% during normal running to allow temporary working space for Cassandra operations. If your cluster is regularly exceeding 70% then you should consider adding capacity or removing data.
Instaclustr Support monitors disk use for all managed clusters and will notify you if your cluster is exceeding recommended levels of disk usage.
In some cases, Cassandra nodes can consume significantly more disk space than reported as loaded data. For this reason, it is important to keep an eye on the raw disk usage on your nodes as well as the volume of loaded data.
Instaclustr reports this information in our console monitoring page as described here: https://www.instaclustr.com/support/documentation/monitoring-information/disk-usage/
We strongly recommend maintaining a minimum of 30% free disk space in normal operations. This is to ensure there is sufficient available space for Cassandra to perform operations such as compaction which temporarily consume additional disk space.
If your cluster is simply filling up with data then it can be easily scaled out by adding additional nodes. To do this, use the add node feature on our console or contact email@example.com for assistance.