east: A B C
west: D
Perhaps you are blocking on a write to D  what's your quorum/rf set up
as?
Bill
On Fri, 20100709 at 10:36 0700, 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
> ec2xxxxxxxxxxx.compute1.amazonaws.com threads 100
> keepgoing
>
> 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
> ec2xxxxxxxxxxx.compute1.amazonaws.com threads 100
> keepgoing
>
> 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
>
