moving Cassandra snapshots to a different disk/server/datacenter

Question

I have Cassandra 1.2.6 cluster running on datacenter A, each node has a solid state drive with somewhat limited space (aprox 50% of disk space is free).

Now I need to implement somehow a way of having automatic backups of each node. Ideally I want to have a way of moving all of the cluster's datafiles to a different disk (standard cheaper disks), or even to a different server in the same datacenter A and possibly moving all the data once in a while to a datacenter B in a different location.

From what I've read I can use snapshots on each node to get the files to copy using whatever tool I want and in this case I have the option to move the data to a different disk/server/datacenter.

My question is, since each of my nodes is about 50% full, taking a snapshot will consume all that space? or the hard links will consume way less space than I anticipate?, if so, is there a better way of doing this, maybe with an already made tool, or everything should be custom made when it comes to this type of backups in Cassandra?

Thanks in advance!

Answer 1

A hard link just creates a new directory entry for the same file (http://en.wikipedia.org/wiki/Hard_link). So a snapshot takes up effectively zero space, but you'll want to clean it up after you're done copying it off to whatever your archive is, because when the "original" sstable is deleted (typically post-compaction), space won't be reclaimed as long as the snapshot reference is still there.

My impression is that tablesnap is the most popular tool for automating backups to s3. It also supports Cassandra incremental backups. If you want more control over where you're backing up to, DataStax OpsCenter supports running a custom script when it takes snapshots.