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 | +61 415 936 359
On 18 Jun 2014, at 7:18 pm, Daniel Chia <danc...@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 <arodr...@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 <arodr...@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
>
>
