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From Andrey Ilinykh <ailin...@gmail.com>
Subject Re: how to take consistant snapshot?
Date Fri, 07 Dec 2012 21:04:15 GMT
Agreed.



On Fri, Dec 7, 2012 at 12:38 PM, Tyler Hobbs <tyler@datastax.com> wrote:

> Right.  I don't personally think incremental backup is useful beyond
> restoring individual nodes unless none of your data happens to reference
> any other rows.
>
>
> On Fri, Dec 7, 2012 at 11:37 AM, Andrey Ilinykh <ailinykh@gmail.com>wrote:
>
>> 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/>
>>>
>>>
>>
>
>
> --
> Tyler Hobbs
> DataStax <http://datastax.com/>
>
>

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