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From Aleksandr Ivanov <ale...@gmail.com>
Subject Re: How to start using incremental repairs?
Date Fri, 26 Aug 2016 06:28:24 GMT
Thanks Alexander.
1. No reads and writes were enabled during repair on keyspace.
2. All repairs were started sequentially on all nodes one by one (new
repair started after repair completeon on previous node)

I'll dig deeper into the logs, maybe there are some records about reason
why some sstables remains unrepaired. But from the first look all repairs
finished without any problems accordingly to log.

пт, 26 Авг 2016 г., 9:18 Alexander DEJANOVSKI <adejanovski@gmail.com>:

> There are 2 main reasons I see for still having unrepaired sstables after
> running nodetool repair -pr :
>
> 1- new data is still flowing in your database after the repair sessions
> were launched, and thus hasn't been repaired
> 2- some repair sessions failed and left unrepaired data on your nodes.
> Incremental repair isn't fond of concurrency, as an SSTable cannot be
> anticompacted and go through validation compaction at the same time. So if
> an SSTable is being anticompacted and another node asks for a merkle tree
> that involves it, it will fail with a message in the system.log saying that
> an sstable cannot be involved in more than one repair session at a time
> (search for validation failures in your cassandra log).
> Best chance to have it succeed IMHO is to run inc repair one node at a
> time.
>
> Le ven. 26 août 2016 à 08:02, Aleksandr Ivanov <alekiv@gmail.com> a
> écrit :
>
>> Thanks for confirmation Paulo. Then my understanding of proccess was
>> correct.
>>
>> I'm curious why I still see unrepaired sstables after performing repair
>> -pr on all nodes in all datacenters...
>>
>> пт, 26 Авг 2016 г., 3:25 Paulo Motta <pauloricardomg@gmail.com>:
>>
>>> 1. Migration procedure is no longer necessary after CASSANDRA-8004, and
>>> since you never ran repair before this would not make any difference
>>> anyway, so just run repair and by default (CASSANDRA-7250) this will
>>> already be incremental.
>>> 2. Incremental repair is not supported with -pr, -local or -st/-et
>>> options, so you should run incremental repair in all nodes in all DCs
>>> sequentially (you should be aware that this will probably generate inter-DC
>>> traffic), no need to disable autocompaction or stopping nodes.
>>>
>>> 2016-08-25 18:27 GMT-03:00 Aleksandr Ivanov <alekiv@gmail.com>:
>>>
>>>> I’m new in Cassandra and trying to figure out how to _start_ using
>>>> incremental repairs. I have seen article about “Migrating to incremental
>>>> repairs” but since I didn’t use repairs before at all and I use Cassandra
>>>> version v3.0.8, then maybe not all steps are needed which are mentioned in
>>>> Datastax article.
>>>> Should I start with full repair or I can start with executing “nodetool
>>>> repair -pr  my_keyspace” on all nodes without autocompaction disabling
and
>>>> node stopping?
>>>>
>>>> I have 6 datacenters with 6 nodes in each DC. Is it enough to run
>>>>  “nodetool repair -pr  my_keyspace” in one DC only or it should be executed
>>>> on all nodes in _all_ DCs?
>>>>
>>>> I have tried to perform “nodetool repair -pr  my_keyspace” on all nodes
>>>> in all datacenters sequentially but I still can see non repaired SSTables
>>>> for my_keyspace   (Repaired at: 0). Is it expected behavior if during
>>>> repair data in my_keyspace wasn’t modified (no writes, no reads)?
>>>>
>>>
>>>

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