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From aaron morton <aa...@thelastpickle.com>
Subject Re: hinted handoff disabling trade-offs
Date Wed, 06 Mar 2013 07:06:38 GMT
The advantage of HH is that it reduces the probability of a DigestMismatch when using a CL
> ONE. A DigestMismatch means the read has to run a second time before returning to the
client. 

>> > - No risk of hinted-handoffs building up
>> > - No risk of hinted-handoffs flooding a node that just came up
See the yaml config settings for the max hint window and the throttling. 

>> > Can anyone suggest any other factors that I'm missing here. Specifically
>> > reasons
>> > not to do this.
If you are doing this for performance first make sure your data model is efficient, that you
are doing the most efficient reads (see my presentation here http://www.datastax.com/events/cassandrasummit2012/presentations),
and your caching is bang on. Then consider if you can tune the CL, and if your client is token
aware so it directs traffic to a node that has it. 

Cheers

-----------------
Aaron Morton
Freelance Cassandra Developer
New Zealand

@aaronmorton
http://www.thelastpickle.com

On 4/03/2013, at 9:19 PM, Michael Kjellman <mkjellman@barracuda.com> wrote:

> Also, if you have enough hints being created that its significantly impacting your heap
I have a feeling things are going to get out of sync very quickly.
> 
> On Mar 4, 2013, at 9:17 PM, "Wz1975" <wz1975@YAHOO.COM> wrote:
> 
>> Why do you think disabling hinted handoff will improve memory usage? 
>> 
>> 
>> Thanks.
>> -Wei
>> 
>> Sent from my Samsung smartphone on AT&T 
>> 
>> 
>> -------- Original message --------
>> Subject: Re: hinted handoff disabling trade-offs 
>> From: Michael Kjellman <mkjellman@barracuda.com> 
>> To: "user@cassandra.apache.org" <user@cassandra.apache.org> 
>> CC: 
>> 
>> 
>> Repair is slow.
>> 
>> On Mar 4, 2013, at 8:07 PM, "Matt Kap" <matvey1414@gmail.com> wrote:
>> 
>> > I am looking to get a second opinion about disabling hinted-handoffs. I
>> > have an application that can tolerate a fair amount of inconsistency
>> > (advertising domain), and so I'm weighting the pros and cons of hinted
>> > handoffs. I'm running Cassandra 1.0, looking to upgrade to 1.1 soon.
>> > 
>> > Pros of disabling hinted handoffs:
>> > - Reduces heap
>> > - Improves GC performance
>> > - No risk of hinted-handoffs building up
>> > - No risk of hinted-handoffs flooding a node that just came up
>> > 
>> > Cons
>> > - Some writes can be lost, at least until repair runs
>> > 
>> > Can anyone suggest any other factors that I'm missing here. Specifically
>> > reasons
>> > not to do this.
>> > 
>> > Cheers!
>> > -Matt
>> 
>> Copy, by Barracuda, helps you store, protect, and share all your amazing 
>> things. Start today: www.copy.com.
> 
> ---------------------------------- 
> Copy, by Barracuda, helps you store, protect, and share all your amazing things. Start
today: www.copy.com.
>   ­­  


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