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From Alain RODRIGUEZ <arodr...@gmail.com>
Subject Re: Multi-DC Repairs and Token Questions
Date Tue, 07 Oct 2014 08:46:50 GMT
Hi guys, sorry about digging this up, but, is this bug also affecting 1.2.x
versions ? I can't see this being backported to 1.2 on the Jira. Was this
bug introduced in 2.0 ?

Anyway, how does nodetool repair -pr behave on a multi DC env, does it make
cross DC repairs or not ? Should we remove the "pr" option in a multi DC
context to remove entropy between DCs ? I mean a repair -pr is supposed to
repair the primary range for the current node, does it also repair
corresponding primary range in other DCs ?

Thanks for insight around this.

2014-06-03 8:06 GMT+02:00 Nick Bailey <nick@datastax.com>:

> See https://issues.apache.org/jira/browse/CASSANDRA-7317
>
>
> On Mon, Jun 2, 2014 at 8:57 PM, Matthew Allen <matthew.j.allen@gmail.com>
> wrote:
>
>> Hi Rameez, Chovatia, (sorry I initially replied to Dwight individually)
>>
>> SN_KEYSPACE and MY_KEYSPACE are just typos (was try to mask out
>> identifiable information), they are same keyspace.
>>
>> Keyspace: SN_KEYSPACE:
>>   Replication Strategy:
>> org.apache.cassandra.locator.NetworkTopologyStrategy
>>   Durable Writes: true
>>     Options: [DC_VIC:2, DC_NSW:2]
>>
>> In a nutshell, replication is working as expected, I'm just confused
>> about token range assignments in a Multi-DC environment and how repairs
>> should work
>>
>> From
>> http://www.datastax.com/documentation/cassandra/1.2/cassandra/configuration/configGenTokens_c.html,
>> it specifies
>>
>> *        "Multiple data center deployments: calculate the tokens for each
>> data center so that the hash range is evenly divided for the nodes in each
>> data center"*
>>
>> Given that nodetool -repair isn't multi-dc aware, in our production 18
>> node cluster (9 nodes in each DC), which of the following token ranges
>> should be used (Murmur3 Partitioner) ?
>>
>> Token range divided evenly over the 2 DC's/18 nodes as below ?
>>
>> Node DC_NSW                    DC_VIC
>> 1    '-9223372036854775808'    '-8198552921648689608'
>> 2    '-7173733806442603408'    '-6148914691236517208'
>> 3    '-5124095576030431008'    '-4099276460824344808'
>> 4    '-3074457345618258608'    '-2049638230412172408'
>> 5    '-1024819115206086208'    '-8'
>> 6    '1024819115206086192'     '2049638230412172392'
>> 7    '3074457345618258592'     '4099276460824344792'
>> 8    '5124095576030430992'     '6148914691236517192'
>> 9    '7173733806442603392'     '8198552921648689592'
>>
>> Or An offset used for DC_VIC (i.e. DC_NSW + 100) ?
>>
>> Node     DC_NSW                 DC_VIC
>> 1     '-9223372036854775808'    '-9223372036854775708'
>> 2     '-7173733806442603407'    '-7173733806442603307'
>> 3     '-5124095576030431006'    '-5124095576030430906'
>> 4     '-3074457345618258605'    '-3074457345618258505'
>> 5     '-1024819115206086204'    '-1024819115206086104'
>> 6     '1024819115206086197'     '1024819115206086297'
>> 7     '3074457345618258598'     '3074457345618258698'
>> 8     '5124095576030430999'     '5124095576030431099'
>> 9     '7173733806442603400'     '7173733806442603500'
>>
>> It's too late for me to switch to vnodes, hope that makes sense, thanks
>>
>> Matt
>>
>>
>>
>> On Thu, May 29, 2014 at 12:01 AM, Rameez Thonnakkal <ssrameez@gmail.com>
>> wrote:
>>
>>> as Chovatia mentioned, the keyspaces seems to be different.
>>> try "Describe keyspace SN_KEYSPACE" and "describe keyspace MY_KEYSPACE"
>>> from CQL.
>>> This will give you an idea about how many replicas are there for these
>>> keyspaces.
>>>
>>>
>>>
>>> On Wed, May 28, 2014 at 11:49 AM, chovatia jaydeep <
>>> chovatia_jaydeep@yahoo.co.in> wrote:
>>>
>>>> What is your partition type? Is
>>>> it org.apache.cassandra.dht.Murmur3Partitioner?
>>>> In your repair command i do see there are two different KeySpaces "MY_KEYSPACE"
>>>> and "SN_KEYSPACE", are these two separate key spaces or typo?
>>>>
>>>> -jaydeep
>>>>
>>>>
>>>>   On Tuesday, 27 May 2014 10:26 PM, Matthew Allen <
>>>> matthew.j.allen@gmail.com> wrote:
>>>>
>>>>
>>>> Hi,
>>>>
>>>> Am a bit confused regarding data ownership in a multi-dc environment.
>>>>
>>>> I have the following setup in a test cluster with a keyspace with
>>>> (placement_strategy = 'NetworkTopologyStrategy' and strategy_options =
>>>> {'DC_NSW':2,'DC_VIC':2};)
>>>>
>>>> Datacenter: DC_NSW
>>>> ==========
>>>> Replicas: 2
>>>> Address         Rack        Status State   Load
>>>> Owns                Token
>>>>
>>>> 0
>>>> nsw1  rack1       Up     Normal  1007.43 MB      100.00%
>>>> -9223372036854775808
>>>> nsw2  rack1       Up     Normal  1008.08 MB      100.00%             0
>>>>
>>>>
>>>> Datacenter: DC_VIC
>>>> ==========
>>>> Replicas: 2
>>>> Address         Rack        Status State   Load
>>>> Owns                Token
>>>>
>>>> 100
>>>> vic1   rack1       Up     Normal  1015.1 MB       100.00%
>>>> -9223372036854775708
>>>> vic2   rack1       Up     Normal  1015.13 MB      100.00%
>>>> 100
>>>>
>>>> My understanding is that both Datacenters have a complete copy of the
>>>> data, but when I run a repair -pr on each of the nodes, the vic hosts only
>>>> take a couple of seconds, while the nsw nodes take about 5 minutes each.
>>>>
>>>> Does this mean that nsw nodes "own" the majority of the data given
>>>> their key ranges and that repairs will need to cross datacenters ?
>>>>
>>>> Thanks
>>>>
>>>> Matt
>>>>
>>>> command>nodetool -h vic1 repair -pr   (takes seconds)
>>>> Starting NodeTool
>>>> [2014-05-28 15:11:02,783] Starting repair command #1, repairing 1
>>>> ranges for keyspace MY_KEYSPACE
>>>> [2014-05-28 15:11:03,110] Repair session
>>>> 76d170f0-e626-11e3-af4e-218541ad23a1 for range
>>>> (-9223372036854775808,-9223372036854775708] finished
>>>> [2014-05-28 15:11:03,110] Repair command #1 finished
>>>> [2014-05-28 15:11:03,126] Nothing to repair for keyspace 'system'
>>>> [2014-05-28 15:11:03,126] Nothing to repair for keyspace 'system_traces'
>>>>
>>>> command>nodetool -h vic2 repair -pr (takes seconds)
>>>> Starting NodeTool
>>>> [2014-05-28 15:11:28,746] Starting repair command #1, repairing 1
>>>> ranges for keyspace MY_KEYSPACE
>>>> [2014-05-28 15:11:28,840] Repair session
>>>> 864b14a0-e626-11e3-9612-07b0c029e3c7 for range (0,100] finished
>>>> [2014-05-28 15:11:28,840] Repair command #1 finished
>>>> [2014-05-28 15:11:28,866] Nothing to repair for keyspace 'system'
>>>> [2014-05-28 15:11:28,866] Nothing to repair for keyspace 'system_traces'
>>>>
>>>> command>nodetool -h nsw1 repair -pr (takes minutes)
>>>> Starting NodeTool
>>>> [2014-05-28 15:11:32,579] Starting repair command #1, repairing 1
>>>> ranges for keyspace SN_KEYSPACE
>>>> [2014-05-28 15:14:07,187] Repair session
>>>> 88966430-e626-11e3-81eb-c991646ac2bf for range (100,-9223372036854775808]
>>>> finished
>>>> [2014-05-28 15:14:07,187] Repair command #1 finished
>>>> [2014-05-28 15:14:11,393] Nothing to repair for keyspace 'system'
>>>> [2014-05-28 15:14:11,440] Nothing to repair for keyspace 'system_traces'
>>>>
>>>> command>nodetool -h nsw2 repair -pr (takes minutes)
>>>> Starting NodeTool
>>>> [2014-05-28 15:14:18,670] Starting repair command #1, repairing 1
>>>> ranges for keyspace SN_KEYSPACE
>>>> [2014-05-28 15:17:27,300] Repair session
>>>> eb936ce0-e626-11e3-81e2-8790242f886e for range (-9223372036854775708,0]
>>>> finished
>>>> [2014-05-28 15:17:27,300] Repair command #1 finished
>>>> [2014-05-28 15:17:32,017] Nothing to repair for keyspace 'system'
>>>> [2014-05-28 15:17:32,064] Nothing to repair for keyspace 'system_traces'
>>>>
>>>>
>>>>
>>>
>>
>

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