cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From aaron morton <>
Subject Re: Replication factor
Date Thu, 24 May 2012 10:00:12 GMT
Your experience is when using CL ONE the Dynamic Snitch is moving local reads off to other
nodes and this is causing spikes in read latency ? 

Did you notice what was happening on the node for the DS to think it was so slow ? Was compaction
or repair going on ? 
Have you played with the badness threshold


Aaron Morton
Freelance Developer

On 24/05/2012, at 5:28 PM, Viktor Jevdokimov wrote:

> Depends on use case. For ours we have another experience and statistics, when turning
dynamic snitch off makes overall latency and spikes much, much lower.
> Best regards / Pagarbiai
> Viktor Jevdokimov
> Senior Developer
> Email:
> Phone: +370 5 212 3063, Fax +370 5 261 0453
> J. Jasinskio 16C, LT-01112 Vilnius, Lithuania
> Follow us on Twitter: @adforminsider
> What is Adform: watch this short video
> <signature-logo29.png>
> Disclaimer: The information contained in this message and attachments is intended solely
for the attention and use of the named addressee and may be confidential. If you are not the
intended recipient, you are reminded that the information remains the property of the sender.
You must not use, disclose, distribute, copy, print or rely on this e-mail. If you have received
this message in error, please contact the sender immediately and irrevocably delete this message
and any copies.
> From: Brandon Williams [] 
> Sent: Thursday, May 24, 2012 02:35
> To:
> Subject: Re: Replication factor
> On Wed, May 23, 2012 at 5:51 AM, Viktor Jevdokimov <>
> > When RF == number of nodes, and you read at CL ONE you will always be reading locally.
> “always be reading locally” – only if Dynamic Snitch is “off”. With dynamic
snitch “on” request may be redirected to other node, which may introduce latency spikes.
> Actually it's preventing spikes, since if it won't read locally that means the local
replica is in worse shape than the rest (compacting, repairing, etc.)
> -Brandon 

View raw message