What does it mean when a shard is down in solr4.4?

[Utkarsh Sengar <ut...@gmail.com>]

I have a 3 node solrcloud cluster with 3 shards for each collection/core.

At times when I rebuild the index say on collectionA on nodeA (shard1) via
UpdateCSV, the "Cloud" status page says that collectionA on nodeA (shard1)
is down.

Observations:
1. Other collections on nodeA work.
2. collectionA on nodeB and nodeC works.
3. nodeA's solr admin is accessible too.

So my questions are:
1. What does it really mean when a shard goes down?
2. How can I recover from that state?

Solr cloud screenshot: http://i.imgur.com/2TgKXiC.png

-- 
Thanks,
-Utkarsh

Re: What does it mean when a shard is down in solr4.4?

[Daniel Collins <da...@gmail.com>]

Well if it is down, it means there is an error on that particular
core/instance of Solr, you would need to check the logs on that instance to
see what the underlying problem is, there is no one root cause.

How to recover: fix the underlying problem and restart that Solr instance?
:)

With the amount of info you've given us, that's about all we can say at
this stage.

Could of Out Of Memory, disk space, error in a document that throws some
odd exception, JVM crash, error writing to transaction log, any one of a
thousand possible reasons.  But that's the explanation at the high level.

Each instance/solr core is a separate entity, they can crash and have
problems, that's why you would normally have multiple replicas per shard,
so you have redundancy.

What your indexing should have noticed was that 1/3rd of your documents
failed to index (since there is no server servicing shard 1, any updates to
that shard will fail)!


On 29 August 2013 18:37, Utkarsh Sengar <ut...@gmail.com> wrote:

> bumping this one, any suggestions?
> I am sure this is solrcloud 101 but I couldn't find documentation anywhere.
>
> Thanks,
> -Utkarsh
>
>
> On Wed, Aug 28, 2013 at 2:37 PM, Utkarsh Sengar <utkarsh2012@gmail.com
> >wrote:
>
> > I have a 3 node solrcloud cluster with 3 shards for each collection/core.
> >
> > At times when I rebuild the index say on collectionA on nodeA (shard1)
> via
> > UpdateCSV, the "Cloud" status page says that collectionA on nodeA
> (shard1)
> > is down.
> >
> > Observations:
> > 1. Other collections on nodeA work.
> > 2. collectionA on nodeB and nodeC works.
> > 3. nodeA's solr admin is accessible too.
> >
> > So my questions are:
> > 1. What does it really mean when a shard goes down?
> > 2. How can I recover from that state?
> >
> > Solr cloud screenshot: http://i.imgur.com/2TgKXiC.png
> >
> > --
> > Thanks,
> > -Utkarsh
> >
>
>
>
> --
> Thanks,
> -Utkarsh
>

Re: What does it mean when a shard is down in solr4.4?

[Utkarsh Sengar <ut...@gmail.com>]

bumping this one, any suggestions?
I am sure this is solrcloud 101 but I couldn't find documentation anywhere.

Thanks,
-Utkarsh


On Wed, Aug 28, 2013 at 2:37 PM, Utkarsh Sengar <ut...@gmail.com>wrote:

> I have a 3 node solrcloud cluster with 3 shards for each collection/core.
>
> At times when I rebuild the index say on collectionA on nodeA (shard1) via
> UpdateCSV, the "Cloud" status page says that collectionA on nodeA (shard1)
> is down.
>
> Observations:
> 1. Other collections on nodeA work.
> 2. collectionA on nodeB and nodeC works.
> 3. nodeA's solr admin is accessible too.
>
> So my questions are:
> 1. What does it really mean when a shard goes down?
> 2. How can I recover from that state?
>
> Solr cloud screenshot: http://i.imgur.com/2TgKXiC.png
>
> --
> Thanks,
> -Utkarsh
>



-- 
Thanks,
-Utkarsh