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From aaron morton <aa...@thelastpickle.com>
Subject Re: Hinted handoff
Date Thu, 07 Mar 2013 05:46:44 GMT
Check the IO utilisation using iostat

You *really* should not need to make HH run faster, if you do there is some thing bad going
on. I would consider dropping the hints and running repair. 

> Data is ~9.5 TB
Do you have 9.5TB on a single node ? 
In the normal case it's best to have around 300 to 500GB per node. With that much data is
will take a week to run repair or replace a failed node. 

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

@aaronmorton
http://www.thelastpickle.com

On 6/03/2013, at 1:22 PM, Kanwar Sangha <kanwar@mavenir.com> wrote:

> Is this correct ?
>  
> I have Raid 0 setup for 16 TB across 8 disks. Each disk is 7.2kRPM with IOPS of 80 per
disk. Data is ~9.5 TB
>  
> So 4K * 80 * 9.5 = 3040 KB ~  23.75 Mb/s.
>  
> So basically I am limited at the disk rather than the n/w
>  
> From: Kanwar Sangha [mailto:kanwar@mavenir.com] 
> Sent: 06 March 2013 15:11
> To: user@cassandra.apache.org
> Subject: RE: Hinted handoff
>  
> After trying to bump up the “hinted_handoff_throttle_in_kb” to 1G/b per sec, It still
does not go above 25Mb/s.  Is there a limitation ?
>  
>  
>  
> From: Kanwar Sangha [mailto:kanwar@mavenir.com] 
> Sent: 06 March 2013 14:41
> To: user@cassandra.apache.org
> Subject: RE: Hinted handoff
>  
> Got the param. thanks
>  
> From: Kanwar Sangha [mailto:kanwar@mavenir.com] 
> Sent: 06 March 2013 13:50
> To: user@cassandra.apache.org
> Subject: Hinted handoff
>  
> Hi – Is there a way to increase the hinted handoff throughput ? I am seeing around
8Mb/s (bits).
>  
> Thanks,
> Kanwar


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