Re: Cassandra JVM heap sizes on EC2

[Janne Jalkanen]

We've been trying to keep the heap as small as possible; the disk access 
penalty on EC2 is big enough - even on instance store - that you want to give 
as much memory to disk caches as you can.  Of course, then you will need to 
keep extra vigilant on your garbage collection and tune various things like 
bloom filters, cache sizes (if using on-heap cache) and sstable size for LCS 
accordingly.

YMMV of course; we're running on m1.xlarge, so we have less RAM to play with 
than you. It all depends on your data size, the size of the hot portion, etc.  
Currently we use 3.5GB for Cassandra 1.2.8, which seems like a good tradeoff 
for our usage patterns.  I tend to bump the heap up and down in .5 GB intervals 
just to see what happens; let it run for a few hours or a day and then check 
Munin graphs to see what the effect was compared to other nodes.

/Janne

On Aug 24, 2013, at 01:12 , David Laube d...@stormpath.com wrote:

 Hi All,
 
 We are evaluating our JVM heap size configuration on Cassandra 1.2.8 and 
 would like to get some feedback from the community as to what the proper JVM 
 heap size should be for cassandra nodes deployed on to Amazon EC2. We are 
 running m2.4xlarge EC2 instances (64GB RAM, 8 core, 2 x 840GB disks) --so we 
 will have plenty of RAM. I've already consulted the docs at 
 http://www.datastax.com/documentation/cassandra/1.2/mobile/cassandra/operations/ops_tune_jvm_c.html
  but would love to hear what is working or not working for you in the wild. 
 Since Datastax cautions against using more than 8GB, I'm wondering if it is 
 even advantageous to use even slightly more.
 
 Thanks,
 -David Laube
 

Re: Commitlog files not getting deleted

[Tupshin Harper]

There is potentially a DSE specific issue that you are running into and you
should probably contact Datastax support to confirm. Also, keep in mind
that Cassandra does recycle it's commitlog files instead of deleting and
recreating them, so you shouldn't expect them to disappear even when the
node isn't being actively written to.

-Tupshin
On Aug 22, 2013 1:40 PM, Jay Svc jaytechg...@gmail.com wrote:

 its DSE 3.1 Cassandra 2.1



 On Thu, Aug 22, 2013 at 10:28 AM, Robert Coli rc...@eventbrite.comwrote:

 On Thu, Aug 22, 2013 at 10:24 AM, Jay Svc jaytechg...@gmail.com wrote:

 In our cluster, the commit log is getting filled up as write progresses.
 It is noticed that once the commit log is flushed to SSTable the commit log
 files are not removed/deleted. The result of that the commit log volume is
 getting filled with commit log files.


 What version of Cassandra? There are some older versions with bugs like
 this, but haven't heard this symptom in a while...

 =Rob

CQLsh assume command

[Vivek Mishra]

Hi,
i am trying to get CQL3 ASSUME command, as it works with Cassandra-cli.

In my example, i have create a table as :

create table default(id blob PRIMARY KEY);

Then after connecting with CQLsh(version 3), i did execute:

assume default(id) values are text;
and then tried to insert a simple record as :

insert into default(id) values('1');

But still i am getting error as:
Bad Request: cannot parse '1' as hex bytes

Any suggestion, what am i doing incorrect here?

-Vivek