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From Jeremiah Jordan <jeremiah.jor...@morningstar.com>
Subject Re: Efficiency of Cross Data Center Replication...?
Date Sun, 20 Nov 2011 18:29:47 GMT
If hinting is off. Read Repair and Manual Repair are the only ways data will get there (just
like when a single node is down).

On Nov 20, 2011, at 6:01 AM, Boris Yen wrote:

> A quick question, what if DC2 is down, and after a while it comes back on. how does the
data get sync to DC2 in this case? (assume hint is disable) 
> 
> Thanks in advance.
> 
> On Thu, Nov 17, 2011 at 10:46 AM, Jeremiah Jordan <jeremiah.jordan@morningstar.com>
wrote:
> Pretty sure data is sent to the coordinating node in DC2 at the same time it is sent
to replicas in DC1, so I would think 10's of milliseconds after the transport time to DC2.
> 
> On Nov 16, 2011, at 3:48 PM, ehershey@gmail.com wrote:
> 
>> On a related note - assuming there are available resources across the board (cpu
and memory on every node, low network latency, non-saturated nics/circuits/disks), what's
a reasonable expectation for timing on replication? Sub-second? Less than five seconds? 
>> 
>> Ernie
>> 
>> On Wed, Nov 16, 2011 at 4:00 PM, Brian Fleming <bigbrianfleming@gmail.com>
wrote:
>> Great - thanks Jake
>> 
>> B.
>> 
>> On Wed, Nov 16, 2011 at 8:40 PM, Jake Luciani <jakers@gmail.com> wrote:
>> the former
>> 
>> 
>> On Wed, Nov 16, 2011 at 3:33 PM, Brian Fleming <bigbrianfleming@gmail.com>
wrote:
>> 
>> Hi All,
>>  
>> I have a question about inter-data centre replication : if you have 2 Data Centers,
each with a local RF of 2 (i.e. total RF of 4) and write to a node in DC1, how efficient is
the replication to DC2 - i.e. is that data :
>>  - replicated over to a single node in DC2 once and internally replicated
>>  or 
>>  - replicated explicitly to two separate nodes?
>> 
>> Obviously from a LAN resource utilisation perspective, the former would be preferable.
>> 
>> Many thanks,
>> 
>> Brian
>> 
>> 
>> 
>> 
>> -- 
>> http://twitter.com/tjake
>> 
>> 
> 
> 


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