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From Alex Major <>
Subject Re: Cassandra crashes
Date Fri, 06 Sep 2013 11:12:05 GMT
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,
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

> 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

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