Anyone? On Tue, Sep 9, 2014 at 8:20 PM, Salman Akram < salman.ak...@northbaysolutions.net> wrote:
> So realistically speaking you cannot have SolrCloud work for 2 data > centers as a redundant solution because no matter how many nodes you add > you still would need at least 1 node in the 2nd center working too. > > So that just leaves with non-SolrCloud solutions. > > "1) Change the replication config to redefine the master and reload the core > or restart Solr." > > That of course is a simple way but the real issue is about the possible > issues and some good practices e.g. normally the scenario would be that > primary data center goes down for few hours and till then we upgrade one of > the slaves in secondary to a master. Now > > - IF there is no lag there won't be any issue in secondary at least but > what if there is lag and one of the files is not completely replicated? > That file would be discarded or there is a possibility that whole index is > not usable? > > - Once the primary comes back how would we now copy the delta from > secondary? Make it a slave of secondary first, replicate the delta and then > set it as a master again? > > In other words is there a good guide out there for this with possible > issues and solutions? Definitely before SolrCloud people would be doing > this and even now SolrCloud doesn't seem practical in quite a few > situations. > > Thanks again!! > > On Tue, Sep 9, 2014 at 8:02 PM, Shawn Heisey <s...@elyograg.org> wrote: > >> On 9/9/2014 8:46 AM, Salman Akram wrote: >> > You mean 3 'data centers' or 'nodes'? I am thinking if we have 2 nodes >> on >> > primary and 1 in secondary and we normally keep the secondary down would >> > that work? Basically secondary network is just for redundancy and won't >> be >> > as fast so normally we won't like to shift traffic there. >> > >> > So can we just have nodes for redundancy and NOT load balancing i.e. it >> has >> > 3 nodes but update is only on one of them? Similarly for the slave >> replicas >> > can we limit the searches to a certain slave or it will be auto >> balanced? >> > >> > Also apart from SOLR cloud is it possible to have multiple master in >> SOLR >> > or a good guide to upgrade a slave to master? >> >> You must have three zookeeper nodes for a redundant setup. If you only >> have two data centers, then you must put at least two of those nodes in >> one data center. If the data center with two zookeeper nodes goes down, >> zookeeper cannot function, which means SolrCloud will not work >> correctly. There is no way to maintain SolrCloud redundancy with only >> two data centers. You might think to add a fourth ZK node and split >> them between the data centers ... except that in that situation, at >> least three nodes must be functional. Two out of four nodes is not >> enough. >> >> A minimal fault-tolerant SolrCloud install is three physical machines. >> Two of them run ZK and Solr, one of them runs ZK only. >> >> If you don't use SolrCloud, then you have two choices to switch masters: >> >> 1) Change the replication config to redefine the master and reload the >> core or restart Solr. >> 2) Write scripts that manually use the replication HTTP API to do all >> your replication, rather than let Solr handle it automatically. You can >> choose the master for every replication with HTTP calls. >> >> https://wiki.apache.org/solr/SolrReplication#HTTP_API >> >> Thanks, >> Shawn >> >> > > > -- > Regards, > > Salman Akram > > -- Regards, Salman Akram
