Hello,
May I know if there is a possibility to add another disk drive in data_file_directories as shown below?
If yes, may I know how Cassandra data such as keyspaces and tables are being stored/shared in disk drive as well?
Thank you for the help.
Hello Miguel, thank you for the info.
From my side, I just want to know if there is such a way to do it.
I have seen the customers that sometimes they don’t have enough disk space to store such large amount of alarm and trend data. So wondering if there is a quick way to solve the issue. One of the methods is to move the cassandra data table to a different disk or expand the disk space.
Hi Min,
Yes, it is possible to add another location in the data_file_directories in the YAML file. This means that ssTables will be divided over both those directories. If you ever want to return back to one location afterward, you will have some manual work. To move back to one disk location, you will need to stop Cassandra (disable the service that DM does not start it), move all the ssTables from the location you are removing to the location you want to keep (this involves quite some manual work if you have a lot of tables), change the yaml file to only point to the one location and then restart Cassandra.
Hi Min,
Not a Cassandra expert, but it will be good to understand why you require two data directories? Checking this nice article:
https://thelastpickle.com/blog/2018/08/22/the-fine-print-when-using-multiple-data-directories.html
Basically they don’t recommend using this feature (or use it as temporary solution). Instead, they recommend to handle this at OS level/hardware level (for example using a LVM you can combine multiple disks).