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 https://github.com/apache/cassandra/blob/trunk/conf/cassandra.yaml#L472 ? Cheers ----------------- Aaron Morton Freelance Developer @aaronmorton http://www.thelastpickle.com 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: viktor.jevdoki...@adform.com > 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 [mailto:dri...@gmail.com] > Sent: Thursday, May 24, 2012 02:35 > To: user@cassandra.apache.org > Subject: Re: Replication factor > > On Wed, May 23, 2012 at 5:51 AM, Viktor Jevdokimov > <viktor.jevdoki...@adform.com> wrote: > > 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
