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From Andrey Ilinykh <ailin...@gmail.com>
Subject Re: how to take consistant snapshot?
Date Fri, 07 Dec 2012 17:37:33 GMT
That's right. But when I have incremental backup on each CF gets flushed
independently. I have "hot" CF which gets flushed every several minutes and
regular CF which gets flushed every hour or so. They have references to
each other and data in sstables is definitely inconsistent.



On Fri, Dec 7, 2012 at 9:28 AM, Tyler Hobbs <tyler@datastax.com> wrote:

> Snapshots trigger a flush first, so data that's currently in the commit
> log will be covered by the snapshot.
>
>
> On Thu, Dec 6, 2012 at 11:52 PM, Andrey Ilinykh <ailinykh@gmail.com>wrote:
>
>>
>>
>>
>> On Thu, Dec 6, 2012 at 7:34 PM, aaron morton <aaron@thelastpickle.com>wrote:
>>
>>> For background
>>>
>>>
>>> http://wiki.apache.org/cassandra/Operations?highlight=%28snapshot%29#Consistent_backups<http://wiki.apache.org/cassandra/Operations?highlight=(snapshot)#Consistent_backups>
>>>
>>> If you it for a single node then yes there is a chance of inconsistency
>>> across CF's.
>>>
>>> If you have mulitple nodes the snashots you take on the later nodes will
>>> help. If you use CL QUOURM for reads you *may* be ok (cannot work it out
>>> quickly.). If you use CL ALL for reads you will be ok. Or you can use
>>> nodetool repair to ensure the data is consistent.
>>>
>>> I'm talking about restoring whole cluster, so all nodes are restored
>> from backup and all of them are inconsistent because they lost data  from
>> commit logs.  It doesn't matter what CL I use, some data may be lost.
>> Cassandra 1.1 supports commit log archiving
>> http://www.datastax.com/docs/1.1/configuration/commitlog_archiving
>>  I think if I store both flushed sstables and commit logs it should solve
>> my problem. I'm wondering if someone has any experience with this feature?
>>
>> Thank you,
>>   Andrey
>>
>
>
>
> --
> Tyler Hobbs
> DataStax <http://datastax.com/>
>
>

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