> Our RF is 2
Are you using the SimpleStrategy or the NetworkTopologyStrategy ? I assumed NTS
in a multi DC setup.
I think I sent before my brain caught up before.
I was thinking that if you had an NTS setup like [ {DC1 : 3}, {DC2: 3},
{DC3:3}] you would change it to
[ {DC1 :3}, {DC2:3}, {DC3 :0}] and then decommission the nodes in DC3.
I dont want to say to much more without knowing how the data is distributed,
the token assignments and the placement strategy.
Cheers
-----------------
Aaron Morton
Freelance Cassandra Developer
@aaronmorton
http://www.thelastpickle.com
On 23/09/2011, at 5:46 AM, Hiren Shah wrote:
> I just started decommissioning one of the nodes. It is streaming data to
> other nodes in the data center, though, which seems waste of time because all
> the nodes will be going away. Wouldn’t it be better to just bring cassandra
> down on these nodes? And then run removetoken or change the topology and
> restart nodes on other two datacenters?
>
> Does it make sense to issue decommission to other nodes before one is
> finished? That should also avoid the unnecessary streaming in theory.
>
> Thanks,
> Hiren
>
> From: Hiren Shah [mailto:hs...@dotomi.com]
> Sent: Thursday, September 22, 2011 8:18 AM
> To: user@cassandra.apache.org
> Subject: RE: Cassandra reconfiguration
>
> Our RF is 2 and we are planning to keep that. Thanks for addressing the
> decommissioning puzzle. That is where I could not find any doc.
>
> Hiren
>
> From: aaron morton [mailto:aa...@thelastpickle.com]
> Sent: Wednesday, September 21, 2011 6:01 PM
> To: user@cassandra.apache.org
> Subject: Re: Cassandra reconfiguration
>
> What are the token assignments and what is the RF ?
>
> Without knowing the details I would guess…
>
> Make the RF changes you want for DC 1 and 2 and repair.
> decomission the nodes in DC3 one at a time.
>
> Cheers
>
> -----------------
> Aaron Morton
> Freelance Cassandra Developer
> @aaronmorton
> http://www.thelastpickle.com
>
> On 22/09/2011, at 5:29 AM, Hiren Shah wrote:
>
>
> Hi,
>
> We have cassandra in production in three data centers with five nodes each.
> We are getting rid of one of the data centers, so I want to reconfig my
> cluster to two data centers, seven nodes each. I first need to shut down DC3.
> I have already shut down traffic to DC3 and am running repairs. My priority
> #1 is to maintain the stability of overall cluster (the two live data
> centers). Some data loss is tolerable, but it will be ideal if I can avoid
> that.
>
> What is the best way to decommission entire data center? Should I issue
> decommission to the nodes one by one? Will that put additional load on
> remaining nodes in DC3? Or should I just shut them down and then run
> removetoken for these nodes? Or is there a better way?
>
> Thanks in advance,
> Hiren Shah
>
