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Posted to user@ignite.apache.org by Neeraj Vaidya <ne...@yahoo.co.in> on 2017/02/24 11:27:28 UTC

[RESOLVED] Cache Entries get lost after multiple nodes started ?

I was able to resolve this.
I set the backup copies of each cache to 1 in the XML file. Now, I can see all data present even if one goes down.
But shouldn't data be automatically pushed/rebalanced to other nodes at the time of shutting down a node ? i.e. by the ignite-core capturing that event and then redistributing that data to live nodes ?
Is maintaining a backup copy the only option to not lose data in case of node failure ?

Regards,
Neeraj

--------------------------------------------
On Fri, 24/2/17, Neeraj Vaidya <ne...@yahoo.co.in> wrote:

 Subject: Re: Cache Entries get lost after multiple nodes started ?
 To: user@ignite.apache.org
 Date: Friday, 24 February, 2017, 2:07 PM
 
 Another thing I noticed is that if I
 stop the node which initially populated the entries, some
 entries are suddenly lost from the cache. This is really
 strange to me.
 
 Regards,
 Neeraj
 
 --------------------------------------------
 On Fri, 24/2/17, Neeraj Vaidya <ne...@yahoo.co.in>
 wrote:
 
  Subject: Re: Cache Entries get lost after multiple nodes
 started ?
  To: user@ignite.apache.org
  Date: Friday, 24 February, 2017, 12:49 PM
  
  I was able to resolve this after I
  changed the Key from AffinityUuid to a simple Integer
 which
  is auto-incremented. How does one explain the behaviour ?
  
  Regards,
  Neeraj
  
  --------------------------------------------
  On Fri, 24/2/17, Neeraj Vaidya <ne...@yahoo.co.in>
  wrote:
  
   Subject: Cache Entries get lost after multiple nodes
  started ?
   To: user@ignite.apache.org
   Date: Friday, 24 February, 2017, 12:05 PM
   
   Hi,
   I have populated a cache containing a K,V pair of
   <AffinityUuid(CustomObject) ,
 CustomClassObject>.
   It gets populated fine when I start a single node
 which is
   responsible for populating the cache. I am able to
  retrieve
   all rows using Zeppelin ignite interpreter or even
 using
   web-console.
   
   However, when I start another node using the same
   configuration file used above, some of the cache
 entries
   just vanish. Is there any reason why this could be
  happening
   ? Note that this node is not performing any data
   manipulation. It is just being started using the
   $IGNITE_HOME\bin\ignite.bat script followed by
  configuration
   file name.
   
   Regards,
   Neeraj
   
  
 

Re: [RESOLVED] Cache Entries get lost after multiple nodes started ?

Posted by vkulichenko <va...@gmail.com>.
Neeraj,

Rebalancing is not happening in this scenario. Any node stop/failure will
cause data loss if there are no backups.

Note that if you have a persistence store with read-through, you may live
without backups, as any lost entry will be reloaded from the store when
needed.

-Val



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Re: [RESOLVED] Cache Entries get lost after multiple nodes started ?

Posted by Andrey Mashenkov <an...@gmail.com>.
Hi Neeraj,

Check if you custom key AffinityUuid implements hashCode() and equals()
methods properly. I would recomment to use Ignite atomic data structures
[1] to generate unique values.

Ignite rebalance data automatically when a node enter\leave topology and
you can see corresponding messaged in logs. However, you should have at
least 1 backup configured.
Rebalance can take a while, so if you'll lose all backup nodes (for primary
that already lost) while rebalance is in progress then obviously data will
be lost.


[1] https://apacheignite.readme.io/docs/id-generator

On Fri, Feb 24, 2017 at 2:27 PM, Neeraj Vaidya <ne...@yahoo.co.in>
wrote:

> I was able to resolve this.
> I set the backup copies of each cache to 1 in the XML file. Now, I can see
> all data present even if one goes down.
> But shouldn't data be automatically pushed/rebalanced to other nodes at
> the time of shutting down a node ? i.e. by the ignite-core capturing that
> event and then redistributing that data to live nodes ?
> Is maintaining a backup copy the only option to not lose data in case of
> node failure ?
>
> Regards,
> Neeraj
>
> --------------------------------------------
> On Fri, 24/2/17, Neeraj Vaidya <ne...@yahoo.co.in> wrote:
>
>  Subject: Re: Cache Entries get lost after multiple nodes started ?
>  To: user@ignite.apache.org
>  Date: Friday, 24 February, 2017, 2:07 PM
>
>  Another thing I noticed is that if I
>  stop the node which initially populated the entries, some
>  entries are suddenly lost from the cache. This is really
>  strange to me.
>
>  Regards,
>  Neeraj
>
>  --------------------------------------------
>  On Fri, 24/2/17, Neeraj Vaidya <ne...@yahoo.co.in>
>  wrote:
>
>   Subject: Re: Cache Entries get lost after multiple nodes
>  started ?
>   To: user@ignite.apache.org
>   Date: Friday, 24 February, 2017, 12:49 PM
>
>   I was able to resolve this after I
>   changed the Key from AffinityUuid to a simple Integer
>  which
>   is auto-incremented. How does one explain the behaviour ?
>
>   Regards,
>   Neeraj
>
>   --------------------------------------------
>   On Fri, 24/2/17, Neeraj Vaidya <ne...@yahoo.co.in>
>   wrote:
>
>    Subject: Cache Entries get lost after multiple nodes
>   started ?
>    To: user@ignite.apache.org
>    Date: Friday, 24 February, 2017, 12:05 PM
>
>    Hi,
>    I have populated a cache containing a K,V pair of
>    <AffinityUuid(CustomObject) ,
>  CustomClassObject>.
>    It gets populated fine when I start a single node
>  which is
>    responsible for populating the cache. I am able to
>   retrieve
>    all rows using Zeppelin ignite interpreter or even
>  using
>    web-console.
>
>    However, when I start another node using the same
>    configuration file used above, some of the cache
>  entries
>    just vanish. Is there any reason why this could be
>   happening
>    ? Note that this node is not performing any data
>    manipulation. It is just being started using the
>    $IGNITE_HOME\bin\ignite.bat script followed by
>   configuration
>    file name.
>
>    Regards,
>    Neeraj
>
>
>
>


-- 
Best regards,
Andrey V. Mashenkov