Have you changed the appropriate config settings so that Cassandra will run with only 2GB RAM? You shouldn't find the nodes go down.
Check out this blog post http://www.opensourceconnections.com/2013/08/31/building-the-perfect-cassandra-test-environment/, it outlines the configuration settings needed to run Cassandra on 64MB RAM and might give you some insights. On Wed, Sep 4, 2013 at 9:44 AM, Jan Algermissen <jan.algermis...@nordsc.com>wrote: > Hi, > > I have set up C* in a very limited environment: 3 VMs at digitalocean with > 2GB RAM and 40GB SSDs, so my expectations about overall performance are low. > > Keyspace uses replication level of 2. > > I am loading 1.5 Mio rows (each 60 columns of a mix of numbers and small > texts, 300.000 wide rows effektively) in a quite 'agressive' way, using > java-driver and async update statements. > > After a while of importing data, I start seeing timeouts reported by the > driver: > > com.datastax.driver.core.exceptions.WriteTimeoutException: Cassandra > timeout during write query at consistency ONE (1 replica were required but > only 0 acknowledged the write > > and then later, host-unavailability exceptions: > > com.datastax.driver.core.exceptions.UnavailableException: Not enough > replica available for query at consistency ONE (1 required but only 0 > alive). > > Looking at the 3 hosts, I see two C*s went down - which explains that I > still see some writes succeeding (that must be the one host left, > satisfying the consitency level ONE). > > > The logs tell me AFAIU that the servers shutdown due to reaching the heap > size limit. > > I am irritated by the fact that the instances (it seems) shut themselves > down instead of limiting their amount of work. I understand that I need to > tweak the configuration and likely get more RAM, but still, I would > actually be satisfied with reduced service (and likely more timeouts in the > client). Right now it looks as if I would have to slow down the client > 'artificially' to prevent the loss of hosts - does that make sense? > > Can anyone explain whether this is intended behavior, meaning I'll just > have to accept the self-shutdown of the hosts? Or alternatively, what data > I should collect to investigate the cause further? > > Jan > > > > > >
