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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: Replacing disks
Date Mon, 29 Feb 2016 07:52:29 GMT
I wrote that a few days ago:
http://thelastpickle.com/blog/2016/02/25/removing-a-disk-mapping-from-cassandra.html

I believe this might help you.

C*heers,
-----------------------

Alain Rodriguez - alain@thelastpickle.com
France

The Last Pickle - Apache Cassandra Consulting
http <http://www.thelastpickle.com/>:// <http://www.thelastpickle.com/>
www.thelastpickle.com
Le 28 févr. 2016 15:17, "Clint Martin" <
clintlmartin@coolfiretechnologies.com> a écrit :

> Code wise, I am not completely familiar with what accomplishes the
> behavior.  But my understanding and experience is that Cass 2.1 picks the
> drive with the most free space when picking a destination for a compaction
> operation.
> (This is an overly simplistic description. Reality is always more
> nuanced.  datastax had a blog post that describes this better as well as
> limitations to the algorithm in 2.1 which are addressed in the 3.x releases
> )
>
> Clint
> On Feb 28, 2016 10:11 AM, "Michał Łowicki" <mlowicki@gmail.com> wrote:
>
>>
>>
>> On Sun, Feb 28, 2016 at 4:00 PM, Clint Martin <
>> clintlmartin@coolfiretechnologies.com> wrote:
>>
>>> Your plan for replacing your 200gb drive sounds good to me. Since you
>>> are running jbod, I wouldn't worry about manually redistributing data from
>>> your other disk to the new one. Cassandra will do that for you as it
>>> performs compaction.
>>>
>>
>> Is this done by pickWriteableDirectory
>> <https://github.com/apache/cassandra/blob/trunk/src/java/org/apache/cassandra/db/Directories.java#L386>
>> ?
>>
>>> While you're doing the drive change, you need to complete the swap and
>>> restart of the node before the hinted handoff window expires on the other
>>> nodes. If you do not complete in time, you'll want to perform a repair on
>>> the node.
>>>
>>
>> Yes. Thanks!
>>
>>
>>>
>>>
>>> Clint
>>> On Feb 28, 2016 9:33 AM, "Michał Łowicki" <mlowicki@gmail.com> wrote:
>>>
>>>> Hi,
>>>>
>>>> I've two disks on single box (500GB + 200GB). data_file_directories in
>>>> cassandra.yaml has two entries. I would like to replace 200GB with 500GB
as
>>>> it's running out of space and to align it with others we've in the cluster.
>>>> The plan is to stop C*, attach new disk, move data from 200GB to new one
>>>> and mount it at the same point in the hierarchy. When done start C*.
>>>>
>>>> Additionally I would like to move some data from the old 500GB to the
>>>> new one to distribute used disk space equally. Probably all related files
>>>> for single SSTable should be moved i.e.
>>>>
>>>> foo-bar-ka-1630184-CompressionInfo.db
>>>>
>>>> foo-bar-ka-1630184-Data.db
>>>>
>>>> foo-bar-ka-1630184-Digest.sha1
>>>>
>>>> foo-bar-ka-1630184-Filter.db
>>>>
>>>> foo-bar-ka-1630184-Index.db
>>>>
>>>> foo-bar-ka-1630184-Statistics.db
>>>>
>>>> foo-bar-ka-1630184-Summary.db
>>>>
>>>> foo-bar-ka-1630184-TOC.txt
>>>>
>>>> Is this something which should work or you see some obstacles? (C*
>>>> 2.1.13).
>>>> --
>>>> BR,
>>>> Michał Łowicki
>>>>
>>>
>>
>>
>> --
>> BR,
>> Michał Łowicki
>>
>

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