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From Charlie Hull <>
Subject Re: Poll: Master-Slave or SolrCloud?
Date Fri, 28 Apr 2017 08:53:07 GMT
Like Sematext, we help clients with both ES and Solr. A particular 
difference is that ES is easier to start with (lots of sensible 
defaults) but then once you have got going (and perchance have thrown 
many millions of items at it) you can run into trouble because you don't 
really understand what's happening under the hood. Solr is still harder 
to get started with but as you're going to have to figure it out anyway 
to get anywhere, you shouldn't end up having to rethink or redo 
everything later.


On 28/04/2017 04:51, David Lee wrote:
> As someone who moved from ES to Solr, I can say that one of the things
> that makes ES so much easier to configure is that the majority of things
> that need to be set for a specific environment are all in pretty much
> one config file. Also, I didn't have to deal with the "magic stuff" that
> many people have talked about where SolrCloud is concerned.
> One of the problems is also do to documentation and user blogs that
> discuss how to use SolrCloud. They all tell you how to create a config
> to run SolrCloud on one system using the -e cloud flag, but then that's
> it. They all seem to avoid discussions of what to do from there in terms
> of best practices in distributing to other nodes. It's out there, but in
> many cases the guides refer to older versions of Solr so sometimes it is
> hard to know what versions people are writing about until you try their
> solutions and nothing works, so you finally figure out they are talking
> about a much older version.
> I moved away from ES to Solr because I prefer the openness of Solr and
> the community participation but I really haven't been very successful in
> deploying this in a production environment at this point.
> I'd say the two things I find that I'm battling with the most are the
> cloud configuration and the work I'm having to do to get even the most
> basic JSON documents indexed correctly (specifically where I need block
> joins, etc.).
> I'm hopeful that the V2 Api will help with the JSON issue, but it would
> be nice to have some documentation that goes more in-depth on how to set
> up additional nodes. Also, even though I use ZK for other parts of my
> application, I have no problem with a version running specifically for
> Solr if it makes this process more straight-forward.
> David
> On 4/27/2017 2:51 AM, Emir Arnautovic wrote:
>> I think creating poll for ES ppl with question: "How do you run master
>> nodes? A) on some data nodes B) dedicated node C) dedicated server"
>> would give some insight how big issue is having ZK and if hiding ZK
>> behind Solr would do any good.
>> Emir
>> On 25.04.2017 23:13, Otis Gospodnetić wrote:
>>> Hi Erick,
>>> Could one run *only* embedded ZK on some SolrCloud nodes, sans any data?
>>> It would be equivalent of dedicated Elasticsearch nodes, which is the
>>> current ES best practice/recommendation.  I've never heard of anyone
>>> being
>>> scared of running 3 dedicated master ES nodes, so if SolrCloud
>>> offered the
>>> same, perhaps even completely hiding ZK from users, that would
>>> present the
>>> same level of complexity (err, simplicity) ES users love about ES.
>>> Don't
>>> want to talk about SolrCloud vs. ES here at all, just trying to share
>>> observations since we work a lot with both Elasticsearch and
>>> Solr(Cloud) at
>>> Sematext.
>>> Otis
>>> --
>>> Monitoring - Log Management - Alerting - Anomaly Detection
>>> Solr & Elasticsearch Consulting Support Training -
>>> On Tue, Apr 25, 2017 at 4:03 PM, Erick Erickson
>>> <>
>>> wrote:
>>>> bq: I read somewhere that you should run your own ZK externally, and
>>>> turn off SolrCloud
>>>> this is a bit confused. "turn off SolrCloud" has nothing to do with
>>>> running ZK internally or externally. SolrCloud requires ZK, whether
>>>> internal or external is irrelevant to the term SolrCloud.
>>>> On to running an external ZK ensemble. Mostly, that's administratively
>>>> by far the safest. If you're running the embedded ZK, then the ZK
>>>> instances are tied to your Solr instance. Now if, for any reason, your
>>>> Solr nodes hosting ZK go down, you lose ZK quorum, can't index.
>>>> etc....
>>>> Now consider a cluster with, say, 100 Solr nodes. Not talking replicas
>>>> in a collection here, I'm talking 100 physical machines. BTW, this is
>>>> not even close to the largest ones I'm aware of. Which three (for
>>>> example) are running ZK? If I want to upgrade Solr I better make
>>>> really sure not to upgrade to of the Solr instances running ZK at once
>>>> if I want my cluster to keep going....
>>>> And, ZK is sensitive to system resources. So putting ZK on a Solr node
>>>> then hosing, say, updates to my Solr cluster can cause ZK to be
>>>> starved for resources.
>>>> This is one of those deals where _functionally_, it's OK to run
>>>> embedded ZK, but administratively it's suspect.
>>>> Best,
>>>> Erick
>>>> On Tue, Apr 25, 2017 at 10:49 AM, Rick Leir <> wrote:
>>>>> All,
>>>>> I read somewhere that you should run your own ZK externally, and turn
>>>> off SolrCloud. Comments please!
>>>>> Rick
>>>>> On April 25, 2017 1:33:31 PM EDT, "Otis Gospodnetić" <
>>>>> wrote:
>>>>>> This is interesting - that ZK is seen as adding so much complexity
>>>>>> that
>>>>>> it
>>>>>> turns people off!
>>>>>> If you think about it, Elasticsearch users have no choice -- except
>>>>>> their
>>>>>> "ZK" is built-in, hidden, so one doesn't have to think about it,
>>>>>> least
>>>>>> not initially.
>>>>>> I think I saw mentions (maybe on user or dev MLs or JIRA) about
>>>>>> potentially, in the future, there only being SolrCloud mode (and
>>>>>> dropping
>>>>>> SolrCloud name in favour of Solr).  If the above comment from Charlie
>>>>>> about
>>>>>> complexity is really true for Solr users, and if that's the reason
>>>>>> why
>>>>>> we
>>>>>> see so few people running SolrCloud today, perhaps that's a good
>>>>>> signal
>>>>>> for
>>>>>> Solr development/priorities in terms of ZK
>>>>>> hiding/automating/embedding/something...
>>>>>> Otis
>>>>>> --
>>>>>> Monitoring - Log Management - Alerting - Anomaly Detection
>>>>>> Solr & Elasticsearch Consulting Support Training -
>>>>>> On Tue, Apr 25, 2017 at 4:50 AM, Charlie Hull <>
>>>>>> wrote:
>>>>>>> On 24/04/2017 15:58, Otis Gospodnetić wrote:
>>>>>>>> Hi,
>>>>>>>> I'm really really surprised here.  Back in 2013 we did a
poll to
>>>>>>>> see
>>>>>> how
>>>>>>>> people were running Master-Slave (4.x back then) and SolrCloud
>>>>>>>> was a
>>>>>> bit
>>>>>>>> more popular than Master-Slave:
>>>>>>>> Here is a fresh new poll with pretty much the same question
>>>>>>>> How do
>>>>>> you
>>>>>>>> run your Solr?
>>>>>> <> -
>>>>>>>> and guess what?  SolrCloud is *not* at all a lot more prevalent
>>>>>>>> than
>>>>>>>> Master-Slave.
>>>>>>>> We definitely see a lot more SolrCloud used by Sematext Solr
>>>>>>>> consulting/support customers, so I'm a bit surprised by the
>>>>>> of
>>>>>>>> this
>>>>>>>> poll so far.
>>>>>>> I'm not particularly surprised. We regularly see clients either
>>>>>>> single nodes or elderly versions of Solr (or even Lucene). Zookeeper
>>>>>> is
>>>>>>> still seen as a bit of a black art. Once you move from 'how do
I run
>>>>>> a
>>>>>>> search engine' to 'how do I manage a cluster of servers with
>>>>>> for
>>>>>>> performance/resilience/failover' you're looking at a completely
>>>>>> set
>>>>>>> of skills and challenges, which I think puts many people off.
>>>>>>> Charlie
>>>>>>>> Is anyone else surprised by this?  See
>>>>>>>> status/854927627748036608
>>>>>>>> Thanks,
>>>>>>>> Otis
>>>>>>>> --
>>>>>>>> Monitoring - Log Management - Alerting - Anomaly Detection
>>>>>>>> Solr & Elasticsearch Consulting Support Training -
>>>>>>>> ---
>>>>>>>> This email has been checked for viruses by AVG.
>>>>>>> --
>>>>>>> Charlie Hull
>>>>>>> Flax - Open Source Enterprise Search
>>>>>>> tel/fax: +44 (0)8700 118334
>>>>>>> mobile:  +44 (0)7767 825828
>>>>>>> web:
>>>>> --
>>>>> Sorry for being brief. Alternate email is rickleir at yahoo dot com
> ---
> This email has been checked for viruses by Avast antivirus software.

Charlie Hull
Flax - Open Source Enterprise Search

tel/fax: +44 (0)8700 118334
mobile:  +44 (0)7767 825828

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