Hello,
we are using Cassandra for storing time series data. We never update, only append; we plan to store 1 year worth of
data, occupying something around 200Gb. I'm trying to understand what will happen when we start deleting the old data.
With size tiered compaction, suppose we have one 160Gb sstable and some smaller tables totalling 40Gb. My understanding
is that, even if we start deleting, we will have to wait for 3 more 160Gb tables to appear, in order to have the first
sstable compacted and the disk space freed. So although we need to store 200Gb worth of data, we'll need something like
800Gb disk space in order to be on the safe side, right?
What would happen instead with leveled compaction? And why is the default sstable size so small (5Mb)? If we need to
store 200Gb, this means we will have 40k sstables; since each one makes 5 files, we'll have 200k files in a single
directory, which we'm afraid will undermine the stability of the file system.
Thank you for your suggestions!
Flavio
