Cassandra Commit Log...can't move

[revelation1]

Best practice for Cassandra is to put the commit log on a separate physical disk. Is that possible with DCOS?

http://docs.datastax.com/en/cassandra/2.1/cassandra/configuration/configCassandra_yaml_r.html#reference_ds_qfg_n1r_1k__commitlog_directory

We also use JBOD but when using disk_type = MOUNT Cassandra puts data in only one resource volume out of the three available.

Is there any way to explicitly define the data and commit log directories? Thank you.

[revelation1]

I have given up on dcos-cassandra on bare metal and thought I would document the big limitations so others can make an early determination.

Bare-metal features missing at this time

• Can't do multiple dedicated Mount points. Many bare metal Cassandra clusters use JBOD.
• Cannot separate commit and data directories. A critical performance requirement for high throughput.
• Buggy (ghosted) mount points. See issues 438.
• No ability to align (group) spark with Cassandra (the typical analysis config)
• No documented way to manage tokens. (add nodes to a cluster with optimal token alignment or replace a failed node without token thrashing.)
• No way to configure cluster traffic for multi-homed machines. A standard cluster traffic isolation technique.

Hopefully no one takes this personally. DCOS is obviously very cool and I look forward to using it when I can.