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From Tyler Hobbs <ty...@datastax.com>
Subject Re: new "nodetool ring" output and unbalanced ring?
Date Mon, 10 Sep 2012 18:48:45 GMT
It leaves some breathing room for fixing mistakes, adding DCs, etc.  The
set of data in a 100 token range is basically the same as a 1 token range:
nothing, statistically speaking.

On Mon, Sep 10, 2012 at 2:21 AM, Guy Incognito <dnd1066@gmail.com> wrote:

>  out of interest, why -100 and not -1 or + 1?  any particular reason?
>
>
> On 06/09/2012 19:17, Tyler Hobbs wrote:
>
> To minimize the impact on the cluster, I would bootstrap a new 1d node at
> (42535295865117307932921825928971026432 - 100), then decommission the 1c
> node at 42535295865117307932921825928971026432 and run cleanup on your
> us-east nodes.
>
> On Thu, Sep 6, 2012 at 1:11 PM, William Oberman <oberman@civicscience.com>wrote:
>
>> Didn't notice the racks!  Of course....
>>
>>  If I change a 1c to a 1d, what would I have to do to make sure data
>> shuffles around correctly?  Repair everywhere?
>>
>>  will
>>
>> On Thu, Sep 6, 2012 at 2:09 PM, Tyler Hobbs <tyler@datastax.com> wrote:
>>
>>> The main issue is that one of your us-east nodes is in rack 1d, while
>>> the restart are in rack 1c.  With NTS and multiple racks, Cassandra will
>>> try use one node from each rack as a replica for a range until it either
>>> meets the RF for the DC, or runs out of racks, in which case it just picks
>>> nodes sequentially going clockwise around the ring (starting from the range
>>> being considered, not the last node that was chosen as a replica).
>>>
>>> To fix this, you'll either need to make the 1d node a 1c node, or make
>>> 42535295865117307932921825928971026432 a 1d node so that you're alternating
>>> racks within that DC.
>>>
>>>
>>> On Thu, Sep 6, 2012 at 12:54 PM, William Oberman <
>>> oberman@civicscience.com> wrote:
>>>
>>>> Hi,
>>>>
>>>>  I recently upgraded from 0.8.x to 1.1.x (through 1.0 briefly) and
>>>> nodetool -ring seems to have changed from "owns" to "effectively owns".
>>>>  "Effectively owns" seems to account for replication factor (RF).  I'm ok
>>>> with all of this, yet I still can't figure out what's up with my cluster.
>>>>  I have a NetworkTopologyStrategy with two data centers (DCs) with
>>>> RF/number nodes in DC combinations of:
>>>> DC Name, RF, # in DC
>>>> analytics, 1, 2
>>>> us-east, 3, 4
>>>> So I'd expect 50% on each analytics node, and 75% for each us-east
>>>> node.  Instead, I have two nodes in us-east with 50/100??? (the other two
>>>> are 75/75 as expected).
>>>>
>>>>  Here is the output of nodetool (all nodes report the same thing):
>>>>  Address         DC          Rack        Status State   Load
>>>>  Effective-Ownership Token
>>>>
>>>>                    127605887595351923798765477786913079296
>>>> x.x.x.x   us-east     1c          Up     Normal  94.57 GB        75.00%
>>>>              0
>>>> x.x.x.x   analytics   1c          Up     Normal  60.64 GB        50.00%
>>>>              1
>>>> x.x.x.x   us-east     1c          Up     Normal  131.76 GB       75.00%
>>>>              42535295865117307932921825928971026432
>>>> x.x.x.x    us-east     1c          Up     Normal  43.45 GB
>>>>  50.00%              85070591730234615865843651857942052864
>>>> x.x.x.x    analytics   1d          Up     Normal  60.88 GB
>>>>  50.00%              85070591730234615865843651857942052865
>>>> x.x.x.x   us-east     1d          Up     Normal  98.56 GB
>>>>  100.00%             127605887595351923798765477786913079296
>>>>
>>>>  If I use cassandra-cli to do "show keyspaces;" I get (and again, all
>>>> nodes report the same thing):
>>>>  Keyspace: civicscience:
>>>>   Replication Strategy:
>>>> org.apache.cassandra.locator.NetworkTopologyStrategy
>>>>   Durable Writes: true
>>>>     Options: [analytics:1, us-east:3]
>>>>  I removed the output about all of my column families (CFs), hopefully
>>>> that doesn't matter.
>>>>
>>>>  Did I compute the tokens wrong?  Is there a combination of nodetool
>>>> commands I can run to migrate the data around to rebalance to 75/75/75/75?
>>>>  I routinely run repair already.  And as the release notes required, I ran
>>>> upgradesstables during the upgrade process.
>>>>
>>>>  Before the upgrade, I was getting analytics = 0%, and us-east = 25%
>>>> on each node, which I expected for "owns".
>>>>
>>>>  will
>>>>
>>>>
>>>
>>>
>>>  --
>>> Tyler Hobbs
>>> DataStax <http://datastax.com/>
>>>
>>>
>>
>>
>>   --
>> Will Oberman
>> Civic Science, Inc.
>> 3030 Penn Avenue., First Floor
>> Pittsburgh, PA 15201
>> (M) 412-480-7835
>> (E) oberman@civicscience.com
>>
>
>
>
> --
> Tyler Hobbs
> DataStax <http://datastax.com/>
>
>
>


-- 
Tyler Hobbs
DataStax <http://datastax.com/>

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