cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Clint Martin <clintlmar...@coolfiretechnologies.com>
Subject Re: Replacing disks
Date Sun, 28 Feb 2016 15:17:39 GMT
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
>

Mime
View raw message