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From Jonathan Ellis <jbel...@gmail.com>
Subject Re: data deleted came back after 9 days.
Date Tue, 17 Aug 2010 19:49:55 GMT
It doesn't have to be disconnected more than GC grace seconds to cause
what you are seeing, it just has to be disconnected at all (thus
missing delete commands).

Thus you need to be running repair more often than gcgrace, or
confident that read repair will handle it for you (which clearly is
not the case for you :).  see
http://wiki.apache.org/cassandra/Operations

On Tue, Aug 17, 2010 at 11:35 AM, Zhong Li <zli@voxeo.com> wrote:
> <GCGraceSeconds>864000</GCGraceSeconds>
> It is default  10 days.
>
> I checked all system.log, all nodes are connected, although not all the
> time, but they reconnected after a few minutes. None of node disconnected
> more than GC grace seconds.
>
> Best,
>
> On Aug 17, 2010, at 11:53 AM, Peter Schuller wrote:
>
>>>> We have 10 nodes cross  5 datacenters. Today I found a strange thing. On
>>>> one node, few data deleted came back after 8-9 days.
>>>>
>>>> The data saved on a node and retrieved/deleted on another node in a
>>>> remote
>>>> datacenter. The CF is a super column.
>>>>
>>>> What is possible causing this?
>>
>> What is your GC grace seconds set to? Is it lower than 8-9 days, and
>> is it possible one or more nodes were disconnected from the remainder
>> of the cluster for a period longer than the GC grace seconds?
>>
>> See: http://wiki.apache.org/cassandra/DistributedDeletes
>>
>> --
>> / Peter Schuller
>
>



-- 
Jonathan Ellis
Project Chair, Apache Cassandra
co-founder of Riptano, the source for professional Cassandra support
http://riptano.com

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