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From Joe Stump <...@joestump.net>
Subject Re: RackAwareStrategy vs RackUnAwareStrategy on AWS EC2 cloud
Date Fri, 09 Jul 2010 17:41:22 GMT
We had similar issues when we started running Cassandra on EC2 between multiple AZ's (not regions;
we're working up to that shortly). We ended up building a rack aware strategy specific to
AWS, which is posted somewhere in JIRA. Basically it uses the AWS API to ensure that replicants
are stored in each AZ. We then ensure that our clients are only reading from nodes in a given
AZ. What I'm guessing is that you're seeing latency issues between regions combined with a
higher consistency level than what we use.

Also, SSL tunnels are hard to scale from the management side. The Amazon folks have told us
that VPNCubed is a better solution for such things.

--Joe


On Jul 9, 2010, at 11:36 AM, maneela a wrote:

> Are there any known performance issues if cassandra cluster launched with RackAwareStrategy
because I see huge performance difference between RackAwareStrategy vs RackUnAwareStrategy.
 Here are details:
> 
> 
> we have a cluster setup with 4 EC2 X large nodes, 3 of them are running in East region
and 4th one is running in West region and they all communicate with each other through VPN
tunnel interface which is only way we found to achieve ring architecture across Amazon cloud
regions:
> 
> 
> we are able to process 3.5K write operations per second when we used RackUnAwareStrategy
whereas 
> 
> :/home/ubuntu/cassandra/contrib/py_stress# ./stress.py -o insert -n 80000 -y regular
-d ec2-xxx-xxx-xxx-xx.compute-1.amazonaws.com --threads 100 --keep-going
> total,interval_op_rate,avg_latency,elapsed_time
> 35935,3593,0.0289930914479,10
> 70531,3459,0.0289145907593,20
> 80000,946,0.0267288666213,30
> 
> whereas we are able to process only 250 write operations per second when we used RackAwareStrategy
> 
> :/home/ubuntu/cassandra/contrib/py_stress# ./stress.py -o insert -n 80000 -y regular
-d ec2-xxx-xxx-xxx-xx.compute-1.amazonaws.com --threads 100 --keep-going
> total,interval_op_rate,avg_latency,elapsed_time
> 2327,232,0.434396038355,10
> 4772,244,0.40946514036,20
> 7383,261,0.384504625415,30
> 9924,254,0.392919449861,40
> 12525,260,0.383832110482,50
> 15158,263,0.378838069983,60
> 17784,262,0.383219807364,70
> 20416,263,0.381646275973,80
> 23030,261,0.382550528602,90
> 25644,261,0.384442176815,100
> 28268,262,0.380935921084,110
> 30910,264,0.377376309224,120
> 33541,263,0.385158945698,130
> 36119,257,0.387976026517,140
> 38735,261,0.382333525368,150
> 41342,260,0.38413751514,160
> 43925,258,0.387684800391,170
> 46642,271,0.36899637237,180
> 49291,264,0.378489510164,190
> 51931,264,0.3793784538,200
> 54573,264,0.378474057217,210
> 57253,268,0.374258003573,220
> 59884,263,0.380020038658,230
> 62484,260,0.387267011954,240
> 64728,224,0.439328571054,250
> 67340,261,0.389221810455,260
> 69920,258,0.386144905127,270
> 72531,261,0.384242234948,280
> 75202,267,0.372129596605,290
> 77843,264,0.354621512291,300
> 80000,215,0.183918378283,310
> 
> Thanks in advance
> 
> Niru
> 


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