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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: EBS SSD <-> Cassandra ?
Date Thu, 19 Jun 2014 08:50:00 GMT
Ok, looks fair enough.

Thanks guys. I would be great to be able to add disks when amount of data
raises and add nodes when throughput increases... :)


2014-06-19 5:27 GMT+02:00 Ben Bromhead <ben@instaclustr.com>:

>
> http://www.datastax.com/documentation/cassandra/1.2/cassandra/architecture/architecturePlanningEC2_c.html
>
> From the link:
>
> EBS volumes are not recommended for Cassandra data volumes for the
> following reasons:
>
> * EBS volumes contend directly for network throughput with standard
> packets. This means that EBS throughput is likely to fail if you saturate a
> network link.
>  * EBS volumes have unreliable performance. I/O performance can be
> exceptionally slow, causing the system to back load reads and writes until
> the entire cluster becomes unresponsive.
>  * Adding capacity by increasing the number of EBS volumes per host does
> not scale. You can easily surpass the ability of the system to keep
> effective buffer caches and concurrently serve requests for all of the data
> it is responsible for managing.
>
> Still applies, especially the network contention and latency issues.
>
> Ben Bromhead
> Instaclustr | www.instaclustr.com | @instaclustr
> <http://twitter.com/instaclustr> | +61 415 936 359
>
> On 18 Jun 2014, at 7:18 pm, Daniel Chia <danchia@coursera.org> wrote:
>
> While they guarantee IOPS, they don't really make any guarantees about
> latency. Since EBS goes over the network, there's so many things in the
> path of getting at your data, I would be concerned with random latency
> spikes, unless proven otherwise.
>
> Thanks,
> Daniel
>
>
> On Wed, Jun 18, 2014 at 1:58 AM, Alain RODRIGUEZ <arodrime@gmail.com>
> wrote:
>
>> In this document it is said :
>>
>>
>>    - Provisioned IOPS (SSD) - Volumes of this type are ideal for the
>>    most demanding I/O intensive, transactional workloads and large relational
>>    or NoSQL databases. This volume type provides the most consistent
>>    performance and allows you to provision the exact level of performance you
>>    need with the most predictable and consistent performance. With this type
>>    of volume you provision exactly what you need, and pay for what you
>>    provision. Once again, you can achieve up to 48,000 IOPS by connecting
>>    multiple volumes together using RAID.
>>
>>
>>
>> 2014-06-18 10:57 GMT+02:00 Alain RODRIGUEZ <arodrime@gmail.com>:
>>
>> Hi,
>>>
>>> I just saw this :
>>> http://aws.amazon.com/fr/blogs/aws/new-ssd-backed-elastic-block-storage/
>>>
>>> Since the problem with EBS was the network, there is no chance that this
>>> hardware architecture might be useful alongside Cassandra, right ?
>>>
>>> Alain
>>>
>>
>>
>
>

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