meaning of eventual consistency in Cassandra ?

[Rajkumar Gupta]

What is the meaning of eventual consistency in Cassandra when nodes in
a single cluster do not mantain the copies of same data but rather
data is distributed among nodes. Since a single peice of data is
recorded at a single place(node),Why wouldn't Cassandra return the
recent value from that single place of record? How do multiple copies
arise in this situation ? Where are the replicas in Cassandra cluster
?

Thanks

For what parts of a social network is Cassandra a good fit ?

[asil klin]

For what parts of a social network is Cassandra a good fit ? Is it
recommendable to throw all social network data into Cassandra
datastore specifically, what about the data for newsfeed generation
from user's network updates ?

Row Cache / Slice Cache

[Daniel Doubleday]

Hi,

we have a couple of use cases with wide rows with a small portion of hot data 
in them.

Example: 

Chatlog: 

{
$userid1-$userid2: [{timestamp: message}, {timestamp: message} ...]
}

People tend to check only the most recent pages. So while the current row cache 
doesn't work with the wide rows I was thinking of adding optional slice / name 
configs to the row cache. 

For example this would say: "cache the last 50 coloumns only"



This would be limited to configurations that allow to easily determine if the 
read / write should go to the cache or not. I would try to make it as simple as 
possible by the restriction that reads can either be served entirely by the 
cache or not use it at all.

I haven't found anything in jira yet and I guess this might be too app-specific 
to be generally interesting but wanted to ask if anybody out there already did 
/ tried something in that direction.

Cheers,

Daniel Doubleday
smeet.com, Berlin

Re: Insert LongType with ruby

[Ryan King]

On Sun, Jan 2, 2011 at 3:45 PM, vicent roca daniel  wrote:
> Hi guys, I need your help.
> I'm trying to insert a column name of type LongType using the ruby wrapper,
> but I can't get it working.
> What I'm trying is something like this:
>    app.insert(:Data, 'device1-cpu', { Time.now => 1234.to_s})
> The columnNames are tye TimeStamp. this way I got an ordened record by time.
> I think I'm not inserting a correct value here. ¿any thoughts ?

What error are you getting?

-ryan

Re: cassandra ruby undefined method

[Ryan King]

On Sat, Jan 1, 2011 at 2:42 PM, vicent roca daniel  wrote:
> Hi guys, I'm new in this list && Cassandra :)
> I'm playing with Cassandra with the ruby wrapper, and I can't figurate out
> what's happing with this error...
> I have this:
> app = Cassandra.new('AOM', servers = "127.0.0.1:9160", :transport_wrapper =>
> Thrift::FramedTransport)
> app.insert(blahh)  --> works OK
> app.get(blah) --> works OK
> but..
> app.get_slice() or get_count(), multiget_slice,etc...  this dont work.
> ruby-1.9.2-p0 > app.get_slice()
> NoMethodError: undefined method `get_slice' for #
> ruby-1.9.2-p0 > app.get_slice()
> NoMethodError: undefined method `get_slice' for #
> I don't know what to try. I'm going nutch here :)

Have you read the README at https://github.com/fauna/cassandra/ ?

-ryan

Re: Row Cache / Slice Cache

[Jonathan Ellis]

While I think "adaptively cache just hot parts of the row wherever
they are" is not feasible, the limitations you describe should be
fine.  I think it's a clever idea, and probably widely useful.

On Mon, Jan 3, 2011 at 10:48 AM, Daniel Doubleday
 wrote:
> Hi,
>
> we have a couple of use cases with wide rows with a small portion of hot data 
> in them.
>
> Example:
>
> Chatlog:
>
> {
>        $userid1-$userid2: [{timestamp: message}, {timestamp: message} ...]
> }
>
> People tend to check only the most recent pages. So while the current row 
> cache doesn't work with the wide rows I was thinking of adding optional slice 
> / name configs to the row cache.
>
> For example this would say: "cache the last 50 coloumns only"
>
>    RowsCached="1" RowCacheLimit="50" RowCacheReversed="true"
> />
>
> This would be limited to configurations that allow to easily determine if the 
> read / write should go to the cache or not. I would try to make it as simple 
> as possible by the restriction that reads can either be served entirely by 
> the cache or not use it at all.
>
> I haven't found anything in jira yet and I guess this might be too 
> app-specific to be generally interesting but wanted to ask if anybody out 
> there already did / tried something in that direction.
>
> Cheers,
>
> Daniel Doubleday
> smeet.com, Berlin



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

Re: Insert LongType with ruby

[vicent roca daniel]

Hi Ryan,

When I insert the column, I don't get  any error. But, when I inspect the
contents, I don't see a valid number.
also, If I try to do a range query, I'm not getting the expected results.

On Mon, Jan 3, 2011 at 6:02 PM, Ryan King  wrote:

> On Sun, Jan 2, 2011 at 3:45 PM, vicent roca daniel 
> wrote:
> > Hi guys, I need your help.
> > I'm trying to insert a column name of type LongType using the ruby
> wrapper,
> > but I can't get it working.
> > What I'm trying is something like this:
> >app.insert(:Data, 'device1-cpu', { Time.now => 1234.to_s})
> > The columnNames are tye TimeStamp. this way I got an ordened record by
> time.
> > I think I'm not inserting a correct value here. ¿any thoughts ?
>
> What error are you getting?
>
> -ryan
>

Re: cassandra ruby undefined method

[vicent roca daniel]

Sorry for this message. I realize that I was doing it wrong.

Thanks ryan.

On Mon, Jan 3, 2011 at 6:03 PM, Ryan King  wrote:

> On Sat, Jan 1, 2011 at 2:42 PM, vicent roca daniel 
> wrote:
> > Hi guys, I'm new in this list && Cassandra :)
> > I'm playing with Cassandra with the ruby wrapper, and I can't figurate
> out
> > what's happing with this error...
> > I have this:
> > app = Cassandra.new('AOM', servers = "127.0.0.1:9160",
> :transport_wrapper =>
> > Thrift::FramedTransport)
> > app.insert(blahh)  --> works OK
> > app.get(blah) --> works OK
> > but..
> > app.get_slice() or get_count(), multiget_slice,etc...  this dont work.
> > ruby-1.9.2-p0 > app.get_slice()
> > NoMethodError: undefined method `get_slice' for #
> > ruby-1.9.2-p0 > app.get_slice()
> > NoMethodError: undefined method `get_slice' for #
> > I don't know what to try. I'm going nutch here :)
>
> Have you read the README at https://github.com/fauna/cassandra/ ?
>
> -ryan
>

Re: Insert LongType with ruby

[Ryan King]

On Mon, Jan 3, 2011 at 9:32 AM, vicent roca daniel  wrote:
> Hi Ryan,
> When I insert the column, I don't get  any error. But, when I inspect the
> contents, I don't see a valid number.
> also, If I try to do a range query, I'm not getting the expected results.

Please show the code you're using.

-ryan

Re: Reclaim deleted rows space

[Peter Schuller]

> Lets assume I have:
> * single 100GB SSTable file
> * min compaction threshold is set to 2
> If I delete rows which are located in this file. Is the only way to "clean"
> the deleted rows is by inserting another 100GB of data or by triggering a
> painful major compaction?

Major compaction does it, but only if GCGraceSeconds has elapsed. See:

   http://spyced.blogspot.com/2010/02/distributed-deletes-in-cassandra.html

-- 
/ Peter Schuller

Re: Reclaim deleted rows space

[Peter Schuller]

> Major compaction does it, but only if GCGraceSeconds has elapsed. See:
>
>   http://spyced.blogspot.com/2010/02/distributed-deletes-in-cassandra.html

But to be clear, under the assumption that your data is a lot smaller
than the tombstones, a major compaction will definitely reclaim space
even if GCGraceSeconds has not elapsed. So actually my original
response is a bit misleading.

-- 
/ Peter Schuller

Re: meaning of eventual consistency in Cassandra ?

[Peter Schuller]

> What is the meaning of eventual consistency in Cassandra when nodes in
> a single cluster do not mantain the copies of same data but rather
> data is distributed among nodes. Since a single peice of data is
> recorded at a single place(node),Why wouldn't Cassandra return the
> recent value from that single place of record? How do multiple copies
> arise in this situation ? Where are the replicas in Cassandra cluster
> ?

There is normally not just a single copy. If you run with RF
(replication factor) = 1, you have a single copy. But this is only
useful if you don't care about redundancy at all.

With multiple replicas, the consistency depends on what you're doing.
For example the choice of consistency level (see the levels listed on
http://wiki.apache.org/cassandra/API).

However note that even with RF=1, there are some things that are still
only "eventual". For example if you submit a batch mutation,
concurrent readers may see a partially applied batch mutation for a
given row even though it is only being written to a single node.

-- 
/ Peter Schuller

Re: meaning of eventual consistency in Cassandra ?

[Rajkumar Gupta]

This means that nodes in cassandra cluster contain data that has been
sharded onto serveral nodes as well as this sharded data may be
replicated further across several nodes ? So cassandra storage
utilizes both sharded as well as replication for load balancing? Is
this correct ?

On Mon, Jan 3, 2011 at 11:28 PM, Peter Schuller
 wrote:
>> What is the meaning of eventual consistency in Cassandra when nodes in
>> a single cluster do not mantain the copies of same data but rather
>> data is distributed among nodes. Since a single peice of data is
>> recorded at a single place(node),Why wouldn't Cassandra return the
>> recent value from that single place of record? How do multiple copies
>> arise in this situation ? Where are the replicas in Cassandra cluster
>> ?
>
> There is normally not just a single copy. If you run with RF
> (replication factor) = 1, you have a single copy. But this is only
> useful if you don't care about redundancy at all.
>
> With multiple replicas, the consistency depends on what you're doing.
> For example the choice of consistency level (see the levels listed on
> http://wiki.apache.org/cassandra/API).
>
> However note that even with RF=1, there are some things that are still
> only "eventual". For example if you submit a batch mutation,
> concurrent readers may see a partially applied batch mutation for a
> given row even though it is only being written to a single node.
>
> --
> / Peter Schuller
>

Re: meaning of eventual consistency in Cassandra ?

[Peter Schuller]

> This means that nodes in cassandra cluster contain data that has been
> sharded onto serveral nodes as well as this sharded data may be
> replicated further across several nodes ? So cassandra storage
> utilizes both sharded as well as replication for load balancing? Is
> this correct ?

Yes, sort of (though depending on your definition of sharding it might
be slightly misleading). In short, replicas (copies of data) is placed
on a number (determined by the replication factor, or RF) of nodes
that participate in a ring where each node has a token associated with
it. The row key (see http://wiki.apache.org/cassandra/DataModel)
determines, along with the so-called 'replication strategy', which
nodes in the ring should have replicas of the data.

I just realized that I couldn't find a wiki page or section of the
Riptano docs that explained the DHT ring and its implications from a
top-down perspective. Am I missing something or is this something that
should be written, anyone?

Probably the best resource on this I found is
http://www.riptano.com/docs/0.6/operations/clustering

If you are interested in the reasoning behind it, I greatly recommend
the Amazon Dynamo paper:

   http://s3.amazonaws.com/AllThingsDistributed/sosp/amazon-dynamo-sosp2007.pdf

Cassandra does not exactly implement what is described, but it is
strongly inspired by it.

-- 
/ Peter Schuller

Re: Insert LongType with ruby

[vicent roca daniel]

Hi again!
code:

require 'rubygems'
require 'cassandra'

app = Cassandra.new('AOM', servers = "127.0.0.1:9160")
app.insert(:NumData, 'device1-cpu', { Time.now => 10.to_s })



storag-confl.xm.






Thanks!!


On Mon, Jan 3, 2011 at 6:52 PM, Ryan King  wrote:

> On Mon, Jan 3, 2011 at 9:32 AM, vicent roca daniel 
> wrote:
> > Hi Ryan,
> > When I insert the column, I don't get  any error. But, when I inspect the
> > contents, I don't see a valid number.
> > also, If I try to do a range query, I'm not getting the expected results.
>
> Please show the code you're using.
>
> -ryan
>

Re: Insert LongType with ruby

[Ryan King]

On Mon, Jan 3, 2011 at 12:56 PM, vicent roca daniel  wrote:
> Hi again!
> code:
> require 'rubygems'
> require 'cassandra'
> app = Cassandra.new('AOM', servers = "127.0.0.1:9160")
> app.insert(:NumData, 'device1-cpu', { Time.now => 10.to_s })

I'm going to assume you're getting an exception here? I think you need
to convert the time to a string.

> 
> storag-confl.xm.
> 
> 
> 
>
> Thanks!!

-ryan

Re: Insert LongType with ruby

[vicent roca daniel]

hi,
no I'n not getting any exception.
The value gets inserted withou problem.

If I try to convert to string I get:
Cassandra::Comparable::TypeError: Expected "2011-01-03 22:14:40 +0100" to
cast to a Cassandra::Long (invalid bytecount)
from
/Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/long.rb:20:in
`initialize'
from
/Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/0.6/columns.rb:10:in
`new'
from
/Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/0.6/columns.rb:10:in
`_standard_insert_mutation'
from
/Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
`block in insert'
from
/Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
`each'
from
/Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
`collect'
from
/Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
`insert'
from (irb):6
from /Users/armandolalala/.rvm/rubies/ruby-1.9.2-p0/bin/irb:17:in `'


On Mon, Jan 3, 2011 at 10:06 PM, Ryan King  wrote:

> On Mon, Jan 3, 2011 at 12:56 PM, vicent roca daniel 
> wrote:
> > Hi again!
> > code:
> > require 'rubygems'
> > require 'cassandra'
> > app = Cassandra.new('AOM', servers = "127.0.0.1:9160")
> > app.insert(:NumData, 'device1-cpu', { Time.now => 10.to_s })
>
> I'm going to assume you're getting an exception here? I think you need
> to convert the time to a string.
>
> > 
> > storag-confl.xm.
> > 
> > 
> > 
> >
> > Thanks!!
>
> -ryan
>

Re: Insert LongType with ruby

[Ryan King]

On Mon, Jan 3, 2011 at 1:15 PM, vicent roca daniel  wrote:
> hi,
> no I'n not getting any exception.

Then what problem are you seeing?

-ryan

> The value gets inserted withou problem.
> If I try to convert to string I get:
> Cassandra::Comparable::TypeError: Expected "2011-01-03 22:14:40 +0100" to
> cast to a Cassandra::Long (invalid bytecount)
> from
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/long.rb:20:in
> `initialize'
> from
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/0.6/columns.rb:10:in
> `new'
> from
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/0.6/columns.rb:10:in
> `_standard_insert_mutation'
> from
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
> `block in insert'
> from
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
> `each'
> from
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
> `collect'
> from
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
> `insert'
> from (irb):6
> from /Users/armandolalala/.rvm/rubies/ruby-1.9.2-p0/bin/irb:17:in `'
>
> On Mon, Jan 3, 2011 at 10:06 PM, Ryan King  wrote:
>>
>> On Mon, Jan 3, 2011 at 12:56 PM, vicent roca daniel 
>> wrote:
>> > Hi again!
>> > code:
>> > require 'rubygems'
>> > require 'cassandra'
>> > app = Cassandra.new('AOM', servers = "127.0.0.1:9160")
>> > app.insert(:NumData, 'device1-cpu', { Time.now => 10.to_s })
>>
>> I'm going to assume you're getting an exception here? I think you need
>> to convert the time to a string.
>>
>> > 
>> > storag-confl.xm.
>> > 
>> > 
>> > 
>> >
>> > Thanks!!
>>
>> -ryan
>
>

Re: Insert LongType with ruby

[vicent roca daniel]

The problem I think I have is that I think I'm not storing the correct
value.
If I do this (for example):

app.insert(:NumData, 'device1-cpu', { Time.now + 1 minut => 10.to_s })
app.insert(:NumData, 'device1-cpu', { Time.now + 1 minu => 10.to_s })
app.insert(:NumData, 'device1-cpu', { Time.now + 1 minu => 10.to_s })
app.insert(:NumData, 'device1-cpu', { Time.now + 1 minu => 10.to_s })

and I do a get query with :start=> first_Time.now and :finish=> the second
Time, I should get two columns, but I'm getting none.
I suspect that the column name is not a valid Time.

¿That make sense?
I'm really new, so please, understand me if I did something crazy :)


On Mon, Jan 3, 2011 at 10:17 PM, Ryan King  wrote:

> On Mon, Jan 3, 2011 at 1:15 PM, vicent roca daniel 
> wrote:
> > hi,
> > no I'n not getting any exception.
>
> Then what problem are you seeing?
>
> -ryan
>
> > The value gets inserted withou problem.
> > If I try to convert to string I get:
> > Cassandra::Comparable::TypeError: Expected "2011-01-03 22:14:40 +0100" to
> > cast to a Cassandra::Long (invalid bytecount)
> > from
> >
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/long.rb:20:in
> > `initialize'
> > from
> >
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/0.6/columns.rb:10:in
> > `new'
> > from
> >
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/0.6/columns.rb:10:in
> > `_standard_insert_mutation'
> > from
> >
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
> > `block in insert'
> > from
> >
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
> > `each'
> > from
> >
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
> > `collect'
> > from
> >
> /Users/armandolalala/.rvm/gems/ruby-1.9.2-p0/gems/cassandra-0.9.0/lib/cassandra/cassandra.rb:125:in
> > `insert'
> > from (irb):6
> > from /Users/armandolalala/.rvm/rubies/ruby-1.9.2-p0/bin/irb:17:in
> `'
> >
> > On Mon, Jan 3, 2011 at 10:06 PM, Ryan King  wrote:
> >>
> >> On Mon, Jan 3, 2011 at 12:56 PM, vicent roca daniel 
> >> wrote:
> >> > Hi again!
> >> > code:
> >> > require 'rubygems'
> >> > require 'cassandra'
> >> > app = Cassandra.new('AOM', servers = "127.0.0.1:9160")
> >> > app.insert(:NumData, 'device1-cpu', { Time.now => 10.to_s })
> >>
> >> I'm going to assume you're getting an exception here? I think you need
> >> to convert the time to a string.
> >>
> >> > 
> >> > storag-confl.xm.
> >> > 
> >> > 
> >> > 
> >> >
> >> > Thanks!!
> >>
> >> -ryan
> >
> >
>

How can I correct this Cassandra load imbalance?

[ian douglas]

Hi everyone,

I've been lurking in the #cassandra IRC channel lately looking for help 
on this, but wanted to try the mailing list as well.


We have 3 nodes, and last week it was suggested that I run 'nodetool 
move' to reset our token values on the 3 nodes because they were 
randomly assigned when starting the nodes the first time.


Our ReplicationFactor is set to 2, and we're using the Random partitioner.

Our row min/max/mean values are mostly the same, but have some small 
discrepancies, but for one of our column families, we have a pretty 
varied disk space live/total count. We'd expect that after issuing a 
"nodetool move" and "nodetool cleanup" on each node (and waiting for 
each to complete before repeating on the next node) that the data load 
would be more balanced, and give us approximately the same disk load on 
all 3 nodes.


nodetool ring:
Address   Status Load  
Range  Ring
   
113427455640312821154458202477256070485
10.242.142.16 Up 2.66 GB   
0  |<--|
10.242.142.111Up 1.24 GB   
56713727820156410577229101238628035243 |   |
10.242.6.242  Up 5.86 GB   
113427455640312821154458202477256070485|-->|


Disk space used (live/total) and row size min/max/mean for each of the 
nodes for the largest ColumnFamily of about a dozen CF's (all are 
defined on each node. I added commas for readability:


Node 1:
Column Family: UserGameshareData
Space used (live): 1,992,054,724
Space used (total): 1,992,054,724
Compacted row minimum size: 307
Compacted row maximum size: 123,498
Compacted row mean size: 1,409

Node 2:
Column Family: UserGameshareData
Space used (live): 782,974,992
Space used (total): 806,168,719
Compacted row minimum size: 306
Compacted row maximum size: 88,379
Compacted row mean size: 1,405

Node 3:
Column Family: UserGameshareData
Space used (live): 4,435,011,932
Space used (total): 4,435,011,932
Compacted row minimum size: 306
Compacted row maximum size: 68,636
Compacted row mean size: 1,387


We also have a cron job running every night that runs a 'nodetool 
cleanup' on one of the nodes (day of year % number of nodes).


I'm happy to share any additional information that can help us balance 
things a little bit better. I had debated setting our ReplicationFactor 
to 3 to see if our nodes eventually copied data to every node.


Cheers,
Ian Douglas, Armor Games

Does Cassandra run better on Amazon EC2 or Rackspace cloud servers?

[Cassy Andra]

My company is looking to develop a software prototype based off Cassandra in
the cloud. We except to run 5 - 10 NoSQL servers for the prototype. I've
read online (Jonathan Ellis was pretty vocal about this) that EC2 has some
I/O issues. Is the general consensus to run Cassandra on EC2 or Rackspace?
What are the pros + cons?

Re: Does Cassandra run better on Amazon EC2 or Rackspace cloud servers?

[Ryan King]

On Mon, Jan 3, 2011 at 3:04 PM, Cassy Andra  wrote:
> My company is looking to develop a software prototype based off Cassandra in
> the cloud. We except to run 5 - 10 NoSQL servers for the prototype. I've
> read online (Jonathan Ellis was pretty vocal about this) that EC2 has some
> I/O issues. Is the general consensus to run Cassandra on EC2 or Rackspace?
> What are the pros + cons?

I don't know about RAX cloud, but Joe Stump of SimpleGeo did some
benchmarks of ec2 io performance:

http://stu.mp/2009/12/disk-io-and-throughput-benchmarks-on-amazons-ec2.html

-ryan

Re: Does Cassandra run better on Amazon EC2 or Rackspace cloud servers?

[Dave Viner]

Since it's all pay-for-use, you could build your system on both, then do
whatever stress testing you want.

The cassandra part of your app should be unchanged between different cloud
providers.

Personally, I'm using EC2 and don't have any complaints.

Dave Viner


On Mon, Jan 3, 2011 at 3:49 PM, Ryan King  wrote:

> On Mon, Jan 3, 2011 at 3:04 PM, Cassy Andra 
> wrote:
> > My company is looking to develop a software prototype based off Cassandra
> in
> > the cloud. We except to run 5 - 10 NoSQL servers for the prototype. I've
> > read online (Jonathan Ellis was pretty vocal about this) that EC2 has
> some
> > I/O issues. Is the general consensus to run Cassandra on EC2 or
> Rackspace?
> > What are the pros + cons?
>
> I don't know about RAX cloud, but Joe Stump of SimpleGeo did some
> benchmarks of ec2 io performance:
>
> http://stu.mp/2009/12/disk-io-and-throughput-benchmarks-on-amazons-ec2.html
>
> -ryan
>

Re: Does Cassandra run better on Amazon EC2 or Rackspace cloud servers?

[Adrian Cockcroft]

EBS volumes don't work well, but the instance local disks are fine on EC2. Also 
the smaller instance types are a lot slower on I/O than the bigger ones. We are 
using local disk on m2.2xl or 4xl (to get lots of RAM). Don't use the m1.small 
instances.

Adrian

From: Dave Viner mailto:davevi...@gmail.com>>
Reply-To: "user@cassandra.apache.org" 
mailto:user@cassandra.apache.org>>
Date: Mon, 3 Jan 2011 15:54:57 -0800
To: "user@cassandra.apache.org" 
mailto:user@cassandra.apache.org>>
Subject: Re: Does Cassandra run better on Amazon EC2 or Rackspace cloud servers?

Since it's all pay-for-use, you could build your system on both, then do 
whatever stress testing you want.

The cassandra part of your app should be unchanged between different cloud 
providers.

Personally, I'm using EC2 and don't have any complaints.

Dave Viner


On Mon, Jan 3, 2011 at 3:49 PM, Ryan King 
mailto:r...@twitter.com>> wrote:
On Mon, Jan 3, 2011 at 3:04 PM, Cassy Andra 
mailto:cassandral...@gmail.com>> wrote:
> My company is looking to develop a software prototype based off Cassandra in
> the cloud. We except to run 5 - 10 NoSQL servers for the prototype. I've
> read online (Jonathan Ellis was pretty vocal about this) that EC2 has some
> I/O issues. Is the general consensus to run Cassandra on EC2 or Rackspace?
> What are the pros + cons?

I don't know about RAX cloud, but Joe Stump of SimpleGeo did some
benchmarks of ec2 io performance:

http://stu.mp/2009/12/disk-io-and-throughput-benchmarks-on-amazons-ec2.html

-ryan

Where is the email archive older than 2010-08-19?

[wang bin]

Hi All,

I am fresh on Cassandra, and I want to know some topics have been
discussed before.
But I don't known how can I find the old topics before 2010-08-19.
The oldest thread I found is
http://www.mail-archive.com/user@cassandra.apache.org/mail15.html

   Can someone told me?

Thank you.
Bin Wang

Re: Where is the email archive older than 2010-08-19?

[Jonathan Ellis]

http://mail-archives.apache.org/mod_mbox/cassandra-user/

On Mon, Jan 3, 2011 at 11:40 PM, wang bin  wrote:
> Hi All,
>
>     I am fresh on Cassandra, and I want to know some topics have been
> discussed before.
> But I don't known how can I find the old topics before 2010-08-19.
> The oldest thread I found is
> http://www.mail-archive.com/user@cassandra.apache.org/mail15.html
>
>    Can someone told me?
>
> Thank you.
> Bin Wang
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com