Thanks for your quick reply.. JoeI forgot to mentioned that we are
using PropertyFileEndPointSnitch to provide cassandra about our network
topology and below is property file uses by that class
cat
rack.properties10.9.0.6=east:r1b10.9.0.18=east:r1c10.9.0.14=east:r1d10.9.0.10=west:r1adefault=east:rdef
In my first glance, VPNCubed uses openVPN software as part of transport layer
so I did not look into it much deeper. I will work on it to see if it helps in
out set up
we are looking for something like Oracle Primary/Standby solution where write
operations happens only on Primary set of nodes ( in our case nodes those are
running in different AZ in East region) and one copy of each data block should
replicate to the node running in the West region so that read operation can be
available local to any region because we have applications that consume
cassandra data, are running from both East and West regions. we are inclined
to accept write latency between regions because readers won't look for data
immediately and there will be around 5 -10 mins gap between write and read
operations.
Is there any way to mark cassandra node to keep it as just for replication
purpose and not to be as Primary for any data range in the ring?
Niru
--- On Fri, 7/9/10, Joe Stump <j...@joestump.net> wrote:
From: Joe Stump <j...@joestump.net>
Subject: Re: RackAwareStrategy vs RackUnAwareStrategy on AWS EC2 cloud
To: user@cassandra.apache.org
Date: Friday, July 9, 2010, 1:41 PM
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-goingtotal,interval_op_rate,avg_latency,elapsed_time35935,3593,0.0289930914479,1070531,3459,0.0289145907593,2080000,946,0.0267288666213,30
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-goingtotal,interval_op_rate,avg_latency,elapsed_time2327,232,0.434396038355,104772,244,0.40946514036,207383,261,0.384504625415,309924,254,0.392919449861,4012525,260,0.383832110482,5015158,263,0.378838069983,6017784,262,0.383219807364,7020416,263,0.381646275973,8023030,261,0.382550528602,9025644,261,0.384442176815,10028268,262,0.380935921084,11030910,264,0.377376309224,12033541,263,0.385158945698,13036119,257,0.387976026517,14038735,261,0.382333525368,15041342,260,0.38413751514,16043925,258,0.387684800391,17046642,271,0.36899637237,18049291,264,0.378489510164,19051931,264,0.3793784538,20054573,264,0.378474057217,21057253,268,0.374258003573,22059884,263,0.380020038658,23062484,260,0.387267011954,24064728,224,0.439328571054,25067340,261,0.389221810455,26069920,258,0.386144905127,27072531,261,0.384242234948,28075202,267,0.372129596605,29077843,264,0.354621512291,30080000,215,0.183918378283,310
Thanks in advance
Niru
