What's difference between node tool removenode & decommission in 1.2.x

[Frank Stutz <fr...@xoom.com>]

I'm a little bit confused on why the nodetool utility has a decommission and a removenode command.  I speculate that decommission command just informs the other nodes that I'm going offline and does not move the data off that node. Whereas removenode resync's the data/tokens to the other nodes.   Although maybe I'm way off.

In short, I'm trying to remove a node and want to know the a good safe way to make sure its tokens are moved to other nodes.  I will note that the other nodes should already have the data, but I always prefer the safest way to insure data is not lost.

--Frank Stutz
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Re: What's difference between node tool removenode & decommission in 1.2.x

[Robert Coli <rc...@eventbrite.com>]

On Tue, Aug 13, 2013 at 10:06 AM, Jasdeep Hundal <ds...@gmail.com> wrote:

> Removenode will stream the data that node is responsible for from other
> replicas, and AFAIK is generally used when a node is offline and cannot be
> brought back up.
>

removetoken should only be used if the departing node is unavailable or
might have corrupt data on disk. Removetoken involves a (small, in
practice) risk that the node being removetokened had the only copy of a
given piece of data.

=Rob

Re: What's difference between node tool removenode & decommission in 1.2.x

[Frank Stutz <fr...@xoom.com>]

Thanks for clarification.   ;-)


--Frank
On Aug 13, 2013, at 10:06 AM, Jasdeep Hundal <ds...@gmail.com>> wrote:

Decommission moves the data from the node being decommissioned to the other nodes that will now have ownership over the data.

Removenode will stream the data that node is responsible for from other replicas, and AFAIK is generally used when a node is offline and cannot be brought back up.

I think you'll want to go with calling 'nodetool decommission' on the node you're trying to remove here.

Jasdeep


On Tue, Aug 13, 2013 at 10:01 AM, Frank Stutz <fr...@xoom.com>> wrote:
I'm a little bit confused on why the nodetool utility has a decommission and a removenode command.  I speculate that decommission command just informs the other nodes that I'm going offline and does not move the data off that node. Whereas removenode resync's the data/tokens to the other nodes.   Although maybe I'm way off.

In short, I'm trying to remove a node and want to know the a good safe way to make sure its tokens are moved to other nodes.  I will note that the other nodes should already have the data, but I always prefer the safest way to insure data is not lost.

--Frank Stutz
---------------------------------------------------------------------------------
The information transmitted in this email is intended only for the person or entity to which it is addressed, and may contain material confidential to Xoom Corporation, and/or its subsidiary, buyindiaonline.com<http://buyindiaonline.com/> Inc.  Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient(s) is prohibited.   If you received this email in error, please contact the sender and delete the material from your files.






---------------------------------------------------------------------------------
The information transmitted in this email is intended only for the person or entity to which it is addressed, and may contain material confidential to Xoom Corporation, and/or its subsidiary, buyindiaonline.com Inc.  Any review, retransmission, dissemination or other use of, or taking of any action in reliance upon, this information by persons or entities other than the intended recipient(s) is prohibited.   If you received this email in error, please contact the sender and delete the material from your files.

Re: What's difference between node tool removenode & decommission in 1.2.x

[Jasdeep Hundal <ds...@gmail.com>]

Decommission moves the data from the node being decommissioned to the other
nodes that will now have ownership over the data.

Removenode will stream the data that node is responsible for from other
replicas, and AFAIK is generally used when a node is offline and cannot be
brought back up.

I think you'll want to go with calling 'nodetool decommission' on the node
you're trying to remove here.

Jasdeep


On Tue, Aug 13, 2013 at 10:01 AM, Frank Stutz <fr...@xoom.com> wrote:

> I'm a little bit confused on why the nodetool utility has a decommission
> and a removenode command.  I speculate that decommission command just
> informs the other nodes that I'm going offline and does not move the data
> off that node. Whereas removenode resync's the data/tokens to the other
> nodes.   Although maybe I'm way off.
>
> In short, I'm trying to remove a node and want to know the a good safe way
> to make sure its tokens are moved to other nodes.  I will note that the
> other nodes should already have the data, but I always prefer the safest
> way to insure data is not lost.
>
> --Frank Stutz
>
> ---------------------------------------------------------------------------------
> The information transmitted in this email is intended only for the person
> or entity to which it is addressed, and may contain material confidential
> to Xoom Corporation, and/or its subsidiary, buyindiaonline.com Inc.  Any
> review, retransmission, dissemination or other use of, or taking of any
> action in reliance upon, this information by persons or entities other than
> the intended recipient(s) is prohibited.   If you received this email in
> error, please contact the sender and delete the material from your files.
>
>
>