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From William Oberman <ober...@civicscience.com>
Subject Re: Aamzon EC2 & Cassandra to ebs or not..
Date Wed, 09 Mar 2011 17:14:39 GMT
Based on Eric's email, it sounds like EBS is a no go from the start.  But
given your snapshot feedback, it seems like you have to plan on leaving
slack on every disk, and the % of slack depends on the size of a snapshot
relative to the data (given the snapshot shares the disk with the data, at
least temporarily).

will

On Wed, Mar 9, 2011 at 11:59 AM, Sasha Dolgy <sdolgy@gmail.com> wrote:

> Hi will,
>
> Quickly did a snapshot:
>
> nodetool -h 10.0.0.2 -p 8080 snapshot 09032011
>
> The snapshots end up in the data dir for cassandra.  The default is
> /var/lib/cassandra/data/<keyspace>/snapshots/
>
> In this directory i have:  1299689801925-09032011
>
> -sd
>
>
> On Wed, Mar 9, 2011 at 5:54 PM, William Oberman <oberman@civicscience.com>wrote:
>
>> I haven't done backups yet, so I don't know where the data is written.  Is
>> it where the nodetool is run from?  Or local to the instance running
>> cassandra (and there, local to the data directory?).  I assumed it was the
>> latter (not finding docs on that yet), and that would require 2x storage
>> allocated on that instance for 1x data (to have room for the snapshot).  If
>> its the former, then yes, I'd totally run the command from an ephemeral
>> store, and backup to S3.
>>
>> will
>>
>>
>> On Wed, Mar 9, 2011 at 11:48 AM, Sasha Dolgy <sdolgy@gmail.com> wrote:
>>
>>> Hi Will,
>>>
>>> http://wiki.apache.org/cassandra/Operations#Backing_up_data
>>>
>>> <http://wiki.apache.org/cassandra/Operations#Backing_up_data>If the
>>> snapshot is written to the ephemeral storage ... there isn't a cost. (i need
>>> to confirm that)
>>>
>>> You can then move this to an S3 bucket with RDS if you want or full
>>> 99.999999999% redundancy and have it available to developers
>>>
>>> This is what I had in my head....
>>> -sd
>>>
>>>
>>> On Wed, Mar 9, 2011 at 5:39 PM, William Oberman <
>>> oberman@civicscience.com> wrote:
>>>
>>>> I thought nodetool snapshot writes the snapshot locally, requiring 2x of
>>>> expensive storage allocation 24x7 (vs. cheap storage allocation of a ebs
>>>> snapshot).  By that I mean EBS allocation is GB allocated per month costs
at
>>>> one rate, and EBS snapshots are delta compressed copies to S3.
>>>>
>>>> Can you point the snapshot to an external filesystem?
>>>>
>>>> will
>>>>
>>>>
>>
>>
>> --
>> Will Oberman
>> Civic Science, Inc.
>> 3030 Penn Avenue., First Floor
>> Pittsburgh, PA 15201
>> (M) 412-480-7835
>> (E) oberman@civicscience.com
>>
>
>
>
> --
> Sasha Dolgy
> sasha.dolgy@gmail.com
>



-- 
Will Oberman
Civic Science, Inc.
3030 Penn Avenue., First Floor
Pittsburgh, PA 15201
(M) 412-480-7835
(E) oberman@civicscience.com

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